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Big Stone Lake State Park 27 75 75 27 9 27 54 75 9 28 28 T. 123 N. T. 126 N. R. 43 W. R. 44 W. R. 45 W. R. 46 W. R. 47 W. R. 48 W. R. 43 W. R. 44 W. R. 45 W. R. 46 W. R. 47 W. T. 127 N. T. 128 N. T. 129 N. Norcross Herman Donnelly Alberta Chokio Johnson Clinton Barry Beardsley Dumont Wheaton Graceville Round Lake Island Lake Fish Lake Lundberg Lake Barrett Lake Cottonwood Lake Niemackl Lakes Werk Lake Ohlsrud Lake Big Lake Mud Lake Lannon Lake East Toqua Lake West Toqua Lake Gravel Lake Clear Lake Gorder Lake Flax Lake Lake Hattie North Rothwell Lake Barry Lake Lake Traverse Graham Lake River Mustinka Bois de Sioux River Twelvemile Creek 45°45' 46°00' 96°00' 96°15' 96°30' 96°30' 96°15' 96°00' STEVENS COUNTY TRAVERSE COUNTY BIG STONE COUNTY TRAVERSE COUNTY BIG STONE COUNTY STEVENS COUNTY GRANT COUNTY TRAVERSE COUNTY Glacial Lakes State Park Lake Carlos State Park 28 29 114 29 94 9 59 27 27 55 79 94 28 29 104 55 28 55 104 114 27 T. 123 N. T. 124 N. T. 125 N. T. 126 N. R. 40 W. R. 39 W. R. 38 W. R. 37 W. R. 36 W. R. 41 W. R. 40 W. R. 39 W. R. 38 W. R. 37 W. R. 36 W. R. 41 W. R. 42 W. T. 127 N. T. 128 N. T. 129 N. Carlos Alexandria Nelson Westport Sedan Lowry Farwell Kensington Hoffman Barrett Elbow Lake Hancock Villard Long Beach Cyrus Starbuck Glenwood Osakis Island Lake Barrett Lake Thompson Lake Elk Lake Ellingson Lake Peterson Lake Hjermenrud Lake Red Rock Lake Solberg Lake Stowe Lake Quam Lake Eng Lake Freeborn Lake Lake Mary Lobster Lake Lake Williams Crooked Lake Elk Lake Lake Carlos Pomme de Terre Lakes Lake Cyrus Devils Lake Chippewa Lake Lake Andrew Maple Lake Clifford Lake Lake Oscar Lake Thorstad Lake Latoka Lake Mina Lake Darling Lake Le Homme Dieu Lake Victoria Lake Geneva Lake Ida Long Lake Jennie Lake Aldrich Lake Davidson Lake Albert Lake Lake Charlotte Moore Lake Long Lake Hanse Lake Hanson Lake Swan Lake Lake Osakis Smith Lake Herberger Lake Kuntz Lake Page Lake Patchen Lake Lake Reno Leven Lake Marlu Lake Grove Lake Swenoda Lake Goose Lake Scandinavian Lake Gilchrist Lake Lake Linka Rasmuson Lake Lake Minnewaska State Lake Jorgenson Lake Larson Lake Christopherson Lake Mud Lake Pelican Lake Round Lake Swan Lake Villard Lake Amelia Lake Ann Lake John Lake Pike Lake Lybeck Lake McIver Lake Erickson Lake Edwards Lake Nelson Lake Lake Hanson Lake Ben Gilbertson Lake Alice Lake Lake Johanna Lake Simon Westport Lake Lake Emily Wollan Lake Malmedal Lake Irgens Lake Little River Chippewa River East Branch River Chippewa Chippewa 45°30' 95°15' 95°30' 95°45' 95°30' 95°15' 45°45' 46°00' 95°45' 96°00' DOUGLAS COUNTY POPE COUNTY DOUGLAS COUNTY GRANT COUNTY STEVENS COUNTY GRANT COUNTY POPE COUNTY STEVENS COUNTY Gilchrist Brandon River Long Prairie Lake Burgan Glacial Lakes State Park Lake Carlos State Park 28 29 114 29 94 9 9 59 27 27 27 55 55 54 79 59 94 28 29 104 59 55 28 55 104 28 114 27 T. 123 N. T. 124 N. T. 125 N. T. 126 N. R. 40 W. R. 39 W. R. 38 W. R. 37 W. R. 36 W. R. 41 W. R. 42 W. R. 43 W. R. 40 W. R. 39 W. R. 38 W. R. 37 W. R. 36 W. R. 41 W. R. 42 W. R. 43 W. T. 127 N. T. 128 N. T. 129 N. Carlos Alexandria Nelson Westport Sedan Lowry Farwell Kensington Hoffman Barrett Elbow Lake Donnelly Hancock Alberta Morris Villard Long Beach Cyrus Starbuck Glenwood Osakis Round Lake Island Lake Long Lake Cormorant Lake Barrett Lake Thompson Lake Elk Lake Ellingson Lake Peterson Lake Hjermenrud Lake Red Rock Lake Solberg Lake Stowe Lake Quam Lake Eng Lake Freeborn Lake Lake Mary Lobster Lake Lake Williams Crooked Lake Elk Lake Lake Carlos Lundberg Lake Harstad Slough Cottonwood Lake Niemackl Lakes Werk Lake Ohlsrud Lake Clear Lake Gorder Lake Flax Lake Pomme de Terre Lakes Lake Cyrus Devils Lake Chippewa Lake Lake Andrew Maple Lake Clifford Lake Lake Oscar Lake Thorstad Lake Latoka Lake Mina Lake Darling Lake Le Homme Dieu Lake Victoria Lake Geneva Lake Ida Long Lake Jennie Lake Aldrich Lake Davidson Lake Albert Lake Eide Lake Wintermute Lake Lake Charlotte Moore Lake Long Lake Hanse Lake Hanson Lake Swan Lake Lake Hattie Lake Osakis Smith Lake Herberger Lake Kuntz Lake Crystal Lake Page Lake Patchen Lake Lake Reno Leven Lake Grove Lake Swenoda Lake Goose Lake Scandinavian Lake Gilchrist Lake Lake Linka Rasmuson Lake Lake Minnewaska State Lake Jorgenson Lake Larson Lake Christopherson Lake Mud Lake Pelican Lake Round Lake Swan Lake Villard Lake Amelia Lake Ann Lake John Lake Pike Lake Lybeck Lake McIver Lake Erickson Lake Edwards Lake Nelson Lake Lake Hanson Lake Ben Gilbertson Lake Alice Lake Lake Johanna Lake Simon Lake Emily Wollan Lake Malmedal Lake Irgens Lake Little River Terre River Chippewa River Pomme de East Branch River Chippewa Chippewa 45°30' 95°15' 95°30' 95°45' 95°30' 95°15' 45°45' 46°00' 95°45' 96°00' 96°00' DOUGLAS COUNTY POPE COUNTY DOUGLAS COUNTY GRANT COUNTY STEVENS COUNTY GRANT COUNTY POPE COUNTY STEVENS COUNTY Gilchrist Brandon River Long Prairie Lake Burgan Glacial Lakes State Park Lake Carlos State Park Big Stone Lake State Park 27 75 28 29 114 29 94 27 75 27 9 9 59 27 27 27 55 55 54 79 59 94 28 29 104 75 59 55 28 55 104 9 28 28 114 27 T. 123 N. T. 124 N. T. 125 N. T. 126 N. R. 40 W. R. 39 W. R. 38 W. R. 37 W. R. 36 W. T. 124 N. T. 123 N. T. 125 N. T. 126 N. R. 41 W. R. 42 W. R. 43 W. R. 44 W. R. 45 W. R. 46 W. R. 47 W. R. 48 W. R. 49 W. R. 40 W. R. 39 W. R. 38 W. R. 37 W. R. 36 W. R. 41 W. R. 42 W. R. 43 W. R. 44 W. R. 45 W. R. 46 W. R. 47 W. T. 127 N. T. 128 N. T. 129 N. T. 127 N. T. 128 N. T. 129 N. Carlos Alexandria Nelson Westport Sedan Lowry Farwell Kensington Hoffman Barrett Elbow Lake Norcross Herman Donnelly Hancock Alberta Chokio Johnson Clinton Barry Beardsley Browns Valley Dumont Morris Wheaton Villard Graceville Long Beach Cyrus Starbuck Glenwood Osakis Round Lake Island Lake Long Lake Cormorant Lake Barrett Lake Thompson Lake Elk Lake Ellingson Lake Peterson Lake Red Rock Lake Solberg Lake Stowe Lake Quam Lake Eng Lake Freeborn Lake Lake Mary Lobster Lake Lake Williams Crooked Lake Elk Lake Lake Carlos Fish Lake Lundberg Lake Harstad Slough Barrett Lake Cottonwood Lake Niemackl Lakes Werk Lake Ohlsrud Lake Big Lake Big Stone Lake Mud Lake Lannon Lake East Toqua Lake West Toqua Lake Gravel Lake Clear Lake Gorder Lake Flax Lake Pomme de Terre Lakes Lake Cyrus Devils Lake Chippewa Lake Lake Andrew Maple Lake Clifford Lake Lake Oscar Lake Thorstad Lake Latoka Lake Mina Lake Darling Lake Le Homme Dieu Lake Victoria Lake Geneva Lake Ida Long Lake Jennie Lake Aldrich Lake Davidson Lake Albert Lake Eide Lake Wintermute Lake Lake Charlotte Moore Lake Long Lake Hanse Lake Hanson Lake Swan Lake Lake Hattie North Rothwell Lake Barry Lake Lake Osakis Smith Lake Herberger Lake Kuntz Lake Crystal Lake Page Lake Patchen Lake Lake Traverse Graham Lake Lake Reno Leven Lake Marlu Lake Grove Lake Swenoda Lake Goose Lake Scandinavian Lake Gilchrist Lake Lake Linka Rasmuson Lake Lake Minnewaska State Lake Jorgenson Lake Larson Lake Christopherson Lake Mud Lake Pelican Lake Round Lake Swan Lake Villard Lake Amelia Lake Ann Lake John Lake Pike Lake McIver Lake Erickson Lake Edwards Lake Nelson Lake Lake Hanson Lake Ben Gilbertson Lake Alice Lake Lake Johanna Lake Simon Westport Lake Lake Emily Wollan Lake Malmedal Lake Irgens Lake Little River Terre River Chippewa River River Pomme de Mustinka East Branch River Chippewa Chippewa Bois de Sioux River Twelvemile Creek 45°30' 95°15' 95°30' 95°45' 95°30' 95°15' 45°30' 45°45' 45°45' 46°00' 46°00' 95°45' 96°00' 96°15' 96°30' 96°30' 96°15' 96°00' STEVENS COUNTY TRAVERSE COUNTY BIG STONE COUNTY TRAVERSE COUNTY BIG STONE COUNTY STEVENS COUNTY DOUGLAS COUNTY POPE COUNTY DOUGLAS COUNTY GRANT COUNTY STEVENS COUNTY GRANT COUNTY POPE COUNTY STEVENS COUNTY GRANT COUNTY TRAVERSE COUNTY Gilchrist Brandon River Long Prairie Lake Burgan 9 9 59 27 27 55 55 54 79 59 59 28 R. 41 W. R. 42 W. R. 43 W. R. 41 W. R. 42 W. R. 43 W. Hoffman Barrett Elbow Lake Donnelly Hancock Alberta Morris Cyrus Round Lake Island Lake Long Lake Cormorant Lake Barrett Lake Thompson Lake Elk Lake Ellingson Lake Peterson Lake Hjermenrud Lake Solberg Lake Fish Lake Lundberg Lake Harstad Slough Barrett Lake Cottonwood Lake Niemackl Lakes Werk Lake Ohlsrud Lake Big Lake Clear Lake Gorder Lake Flax Lake Pomme de Terre Lakes Lake Cyrus Davidson Lake Albert Lake Eide Lake Wintermute Lake Lake Charlotte Moore Lake Long Lake Hanse Lake Hanson Lake Swan Lake Lake Hattie Crystal Lake Page Lake Patchen Lake Graham Lake Terre River Pomme de 95°45' 95°45' 96°00' 96°00' DOUGLAS COUNTY GRANT COUNTY STEVENS COUNTY GRANT COUNTY POPE COUNTY STEVENS COUNTY Big Stone Lake State Park 28 T. 124 N. T. 123 N. R. 48 W. R. 49 W. Beardsley Browns Valley Big Stone Lake 45°30' 1060 1060 1060 1060 1040 1040 1080 1060 1020 1040 1020 1000 1000 1060 1080 1080 1080 1060 1060 1040 1060 1060 1040 1040 1040 1040 1040 1060 1020 980 980 1000 1020 1020 1040 1080 1060 1060 1020 1020 1280 1280 1260 1280 1300 1180 1260 1240 1220 1160 1160 1180 1200 1240 1220 1200 1180 1160 1140 1220 1200 1180 1200 1180 1160 1160 1200 1180 1140 1200 1200 1220 1240 1240 1260 1240 1260 1220 1280 1260 1280 1300 1300 1300 1280 1260 1220 1200 1320 1260 1240 1320 1300 1280 1300 1320 1320 1320 1340 1340 1360 1200 1240 1260 1240 1280 1320 1220 1300 1300 1280 1280 1320 1220 1200 1180 1140 1120 1140 1140 1120 1160 1340 1340 1100 1100 1320 1380 1400 1340 1360 1360 1360 1260 1380 1380 1340 1380 1320 1340 1360 1360 1360 1360 1320 1320 1320 1260 1260 1280 1300 1300 1360 1360 1340 1360 1360 1200 1200 1340 1340 1380 1380 1380 1380 1340 1120 1120 1240 1240 1360 1360 1360 1360 1360 1360 1360 1360 1360 1360 1340 1360 1340 1280 1300 1360 1260 1260 1360 1320 1320 1300 1320 1340 1320 1320 1300 1280 1280 1260 1200 1180 1180 1180 1200 1180 1180 1180 1120 1220 1220 1200 1360 1380 1360 1320 1320 1200 1180 1180 1200 1360 1280 1200 1160 1160 1220 1260 1260 1280 1260 1240 1240 1240 1260 1340 1200 1220 1200 1180 1220 1220 1220 1220 1240 1240 1240 1200 1240 1300 1340 1340 1300 1300 1280 1280 1280 1140 1140 1140 1140 1140 1140 1200 1200 1200 1200 1240 1220 1320 1320 1320 1320 1340 1340 1180 1200 1060 1060 1100 1340 1340 1340 1380 1340 1060 1400 1380 1360 1380 1380 1320 1300 1380 1360 1360 1260 1260 1260 1240 1240 1260 1180 1180 1100 1160 1160 1160 1140 1120 1140 1140 1080 1080 1080 1080 1100 1120 1100 1120 1120 1180 1160 1160 1160 1140 1080 1080 1060 1260 1160 1280 1120 1120 1100 1100 1100 1100 1100 1200 1060 1060 1360 1380 1400 1060 1140 1220 1220 1400 1360 1340 1200 1220 1200 1200 1160 1160 1180 1180 1140 1140 1120 1120 1240 1120 1140 1120 1100 1100 1100 1100 1100 1100 1060 1060 1080 1140 1120 1120 1120 1140 1160 1160 1240 1200 1080 1080 1080 1080 1080 1180 1200 1220 1160 1120 1080 1080 1400 1380 1120 1100 1100 1080 1060 1140 1080 1220 1100 1080 1140 1120 1100 1200 1160 1120 1140 1120 1100 1080 1080 1100 1100 1100 1080 F’ E’ D’ C’ B’ A’ G’ H’ A B C D E F G H A B C D E F G H F’ E’ D’ C’ B’ A’ G’ H’ A B C D E F G H F’ E’ D’ C’ B’ A’ G’ H’ I c e margin defining eastern e d g e o f O T a q u i f e r a n d L o w e r G oose River group F’ E’ D’ C’ B’ A’ G’ H’ A B C D E F G H Ic e m a r g i n d efi n i n g e a s t e r n edg e o f L G a q u i f e r a n d U p p e r G o o s e R i ver g r o u p A B C D E F G H F’ E’ D’ C’ B’ A’ G’ H’ F’ G’ H’ F G H 3000 200 2000 3000 2000 100 2000 2000 1000 1400 5.80 6.10 5.00 100 1300 1000 1700 1600 3.04 12.60 6000 3.50 STATE OF MINNESOTA DEPARTMENT OF NATURAL RESOURCES DIVISION OF WATERS REGIONAL HYDROGEOLOGIC ASSESSMENT RHA–6, PART B, PLATE 6 OF 6 Sensitivity to Pollution of the Buried Aquifers SENSITIVITY TO POLLUTION OF THE BURIED AQUIFERS By James A. Berg 2008 REGIONAL HYDROGEOLOGIC ASSESSMENT TRAVERSE–GRANT AREA, WEST-CENTRAL MINNESOTA Caution: The information on these maps is a generalized interpretation of the sensitivity of ground water to contamination. The maps are intended to be used for resource protection planning and to help focus the gathering of information for site-specific investigations. FIGURE 1. Geologic sensitivity rating as defined by vertical travel time (Geologic Sensitivity Workgroup, 1991). Ratings are based on the time range required for water at or near the surface to travel vertically into the ground water of interest or a pollution sensitivity target. Tritium and carbon-14 studies indicate the relative ages of ground water. GROUND-WATER TRAVEL TIME, IN LOG 10 HOURS 0 1 2 3 4 5 6 7 Time range for tritium studies SENSITIVITY RATING Time range for carbon-14 studies Hour Day Week Month Year Decade Century Very Low Moderate Very High High Low FIGURE 3. Pollution sensitivity rating matrix. Pollution sensitivity is inversely proportional to the thickness of a protective layer between the top of the aquifer and the nearest overlying recharge surface. Any buried aquifer with less than a 10-foot-thick protective layer between it and an overlying recharge surface is rated very high sensitivity because there is little fine-grained material to increase the time of travel. A thicker overly- ing protective layer provides additional protection to the aquifer, and sensitivity ratings are determined based on the thickness of this layer. Thickness of protective layer between the aquifer and the nearest overlying recharge surface (in feet) VH H M L VL 0 to 10 10 to 20 20 to 30 30 to 40 Greater than 40 Static (nonpumping) water-level data. MAP EXPLANATION FIGURE 2. Generalized cross section showing recharge concepts for buried aquifers considered in the sensitivity evaluations. In this conceptual model of the eastern part of the study area, all recent recharge enters the buried aquifer system at recharge surface 1 (red dotted line). Recharge surface 1 is considered to be at the land surface where till is present, at the bottom of surficial sand deposits and at the bottom of surface water bodies where surficial sand is not present. If less than 10 feet of fine-grained sediment (clay or till) exists between recharge surface 1 and the shallowest underlying buried aquifer, then recent recharge is assumed to move to the bottom of that aquifer to form recharge surface 2. The process and criteria are repeated stepwise for deeper aquifers (recharge surface 3). If shown, ground-water age in years, estimated by carbon-14 isotope analysis. 2000 Map symbols and labels If shown, nitrate as nitrogen concentration equals or exceeds 3 parts per million. 6.08 Sensitivity ratings Estimated vertical travel time for water-borne contaminants to enter an aquifer (pollution sensitivity target). Very High—Hours to months High—Weeks to years Moderate—Years to decades Low—Decades to a century Very Low—A century or more VH H M L VL The DNR Information Center Twin Cities: (651) 296-6157 Minnesota toll free: 1-888-646-6367 Telecommunication device for the hearing impaired (TDD): (651) 296-5484 TDD Minnesota toll free: 1-800-657-3929 DNR web site: http://www.dnr.state.mn.us This information is available in alternative format on request. Equal opportunity to participate in and benefit from programs of the Minnesota Department of Natural Resources is available regardless of race, color, national origin, sex, sexual orientation, marital status, status with regard to public assistance, age, or disability. Discrimination inquiries should be sent to Minnesota DNR, 500 Lafayette Road, St. Paul, MN 55155-4031, or the Equal Opportunity Office, Department of the Interior, Washington, DC 20240. © 2008 State of Minnesota, Department of Natural Resources, and the Regents of the University of Minnesota. This map was compiled and generated using geographic information systems (GIS) technology. Digital data products, including chemistry and geophysical data, are available from DNR Waters at http://www.dnr.state.mn.us/waters. This map was prepared from publicly available information only. Every reasonable effort has been made to ensure the accuracy of the factual data on which this map interpretation is based. However, the Department of Natural Resources does not warrant the accuracy, completeness, or any implied uses of these data. Users may wish to verify critical information; sources include both the references here and information on file in the offices of the Minnesota Geological Survey and the Minnesota Department of Natural Resources. Every effort has been made to ensure the interpretation shown conforms to sound geologic and cartographic principles. This map should not be used to establish legal title, boundaries, or locations of improvements. Base modified from Minnesota Geological Survey, Traverse–Grant Area Regional Hydrogeologic Assessment, Part A, 2006. Project data compiled from 2004 to 2007 at a scale of 1:100,000. Universal Transverse Mercator projection, grid zone 15, 1983 North American datum. Vertical datum is mean sea level. GIS and cartography by Jim Berg and Greg Massaro. Edited by Nick Kroska. Explanation Recent ground-water recharge Recent or mixed ground-water recharge Recharge surface 1 (generally shallow) Recharge surface 2 (generally intermediate) Recharge surface 3 (generally deep) Aquifer 1 CW aquifer OT aquifer Otter Tail River group Crow Wing River group Browerville formation and other unnamed tills Lower Goose River group Surficial aquifer General direction of ground-water flow. Body of water. Ice margin. Line of cross section. Potentiometric contour line. Contour interval is 20 feet. Ground-water recharge from overlying surficial aquifer to buried aquifer. Ground-water leakage through multiple aquifers and fine-grained layers. Lateral ground-water flow. Ground-water discharge from a buried aquifer to surface-water body. Infiltration through a thin layer of overlying, fine-grained material to an underlying aquifer. Unknown source of recent or mixed ground water. Ground-water leakage from an overlying buried aquifer to an underlying buried aquifer. FIGURE 4. LG aquifer—pollution sensitivity and potentiometric surface. The limited-extent LG aquifer in the central and southwestern portion of the study area mostly has very low pollution sensitivity, except where a thin layer of fine-grained material covers the aquifer. This figure shows good agreement between the portions of this aquifer where the sensitivity model predicts very low sensitivity and where vintage tritium values occur. Mixed tritium values and most elevated Cl/Br values occur in areas modeled as low to moderate sensitivity. Except for a few locations near the Pomme de Terre River, the directions of regional ground-water flow are generally to the west and southwest. FIGURE 5. OT aquifer—pollution sensitivity and potentiometric surface. Moderate to very high pollution sensitivity conditions are common for this aquifer in the eastern portion of the study area where the aquifer is covered by a thin layer of fine-grained material. With a few exceptions, this aqui- fer is shown with very low pollution sensitivity in the western portion of the study area where it is mostly covered by thicker layers of fine-grained material. Discharge to the surficial sand and gravel aquifers of the Pomme de Terre and Chippewa rivers in the central portions of the study area is prob- ably a common occurrence. All the vintage tritium values occur in locations that were modeled as very low sensitivity. Most mixed and recent values occur in areas modeled as moderate to very high sensitivity. The west and southwest directions of regional ground-water flow are complicated locally by the Pomme de Terre and Chippewa rivers and associated tributaries. FIGURE 6. CW aquifer—pollution sensitivity and potentiometric surface. The CW aqui- fer is relatively sensitive in eastern Pope and Douglas counties where it is typically the first buried aquifer beneath the sensitive surficial aquifers in that portion of the study area. Smaller sensitive areas exist in other parts of the study area, especially in areas associated with the Pomme de Terre and Chippewa rivers where thick surficial aquifers are present and ground-water leakage from the surficial aquifers to the CW aquifer may be common. Indicators of ground-water residence time generally agree with the pollution sensitivity ratings for the CW aquifer. Most vintage tritium values occur in areas that were modeled as low to very low sensitivity. Five of these vintage samples were also analyzed for carbon-14 age with values ranging from 100 years to 1700 years. Most occurrences of mixed and recent tritium probably resulted from one of the five leakage mechanisms shown on the figure. A regional ground-water divide in eastern Douglas County and northeastern Pope County splits the ground-water flow directions within this aquifer. East of the divide, flow is to the east; flow west of this divide is generally to the southwest with many local complexities created by discharge to local depressions such as Lake Minnewaska and the valleys of the Pomme de Terre and Chippewa rivers. FIGURE 7. Aquifer 1—pollution sensitivity and potentiometric surface. This aquifer was mostly rated as low and very low pollution sensitivity. Most areas of moderate and high sensitivity occur at scattered locations in the eastern portion of the study area beneath the Belgrade-Glenwood area aqui- fer and the eastern portion of the CW aquifer. In these more sensitive areas, leakage through multiple aquifers appears to be the most common mecha- nism. Most of the vintage tritium values occur in areas rated as low or very low sensitivity. Vintage samples analyzed for carbon-14 age had values rang- ing from 100 years to 3000 years. Most of the mixed or recent tritium values that were associated with lower than expected pollution sensitivity ratings occur downgradient from areas of higher sensitivity. FIGURE 8. Western aquifer—pollution sensitivity and potentiomet- ric surface. The mapped area for this aquifer in the western portion of the study area does not have deep or extensive surficial aquifers and the overlying buried aquifer (mostly the OT aquifer) generally has limited extent and thickness. As a result of those conditions, few direct recharge pathways to the western aquifer exist. The few samples from this aquifer that were analyzed for tritium were vintage age and all occurred in areas rated as very low sensitivity. Two of the vintage samples from Big Stone County that were also analyzed for carbon-14 age had values of 200 years and 3000 years. Ground water generally flowed to the west with some local exceptions. DNR Waters 1080 If shown on well symbol, chloride to bromide ratio greater than 175. Tritium age Color indicates tritium age of water sampled in well. Recent—Water entered the ground since about 1953 (10 or more tritium units [TU]). Mixed—Water is a mixture of recent and vintage waters (greater than 1 TU to less than 10 TU). Vintage—Water entered the ground before 1953 (less than or equal to 1 TU). Well not sampled for tritium, but sampled for chloride and bromide. Well and buried aquifer symbols LG aquifer OT aquifer CW aquifer Aquifer 1 Western aquifer INTRODUCTION This plate describes the relative sensitivity of the uppermost, buried sand and gravel aquifers in the study area to surface or near-surface releases of contaminants. Sensitivity to pollution is defined as the ease with which a surface contaminant moving with water might travel to and enter a subsur- face water source. The maps are intended to help local units of government protect and manage their ground-water resources. The uppermost, buried sand and gravel aquifers, as shown on Plates 4 and 5, include the generally shallow LG aquifer in the central portion of the study area; the OT aquifer, which is also relatively shallow in the eastern one-third of the study area (most of Pope and Douglas counties); the CW aquifer and aquifer 1, which were mapped only for the eastern two-thirds and half of the study area respectively; and the western aquifer, which was mapped for only the west- ern one-third of the study area. These aquifers are the primary sensitivity targets for the following discussion. The migration of contaminants in or with water through earth materials is a complex phenomenon that depends on many factors. A regional evalua- tion of sensitivity to contaminants requires some simplifying assumptions. For this report, the permeability factor (the ability of earth materials to trans- mit water) was only evaluated qualitatively. Additionally, this evaluation was based on the assumption of vertical ground-water transport, although horizontal flow dominates in many settings. Finally, the sensitivity ratings are based on vertical travel time of water (Figure 1), not the behavior of specific contaminants. The surficial aquifers were assumed to be highly or very highly sensi- tive almost everywhere in the study area because these aquifers have little or no laterally extensive protective cover (see Figure 4 on Plate 3). No geochemical data were collected to verify directly the sensitivity of surficial aquifers. The surficial aquifer distribution and thickness, however, are important factors in the following pollution sensitivity evaluation of buried sand and gravel aquifers. They are the primary factors controlling recharge water infiltrating to the buried aquifers. DEVELOPMENT OF POLLUTION SENSITIVITY MODEL AND MAPS OF BURIED AQUIFERS The goals of the pollution sensitivity modeling and mapping process were to calculate the thickness of protective material overlying each aquifer and interpret protective thickness as different levels of pollution sensitivity. The pollution sensitivity modeling and mapping process has three steps. The first step is mapping and defining the aquifers and low-permeability geologic units (protective layers) as three-dimensional geographic informa- tion system (GIS) surfaces. The second step is representing aquifer recharge as a series of related elevation surfaces that can be used along with the protective layer thickness calculations. The third step is interpreting the protective thickness calculations as pollution sensitivity. In the first step, the top and bottom elevation surfaces that define aqui- fers and the low-permeability till layers are created as described on Plates 3, 4, and 5. These surfaces are represented in three dimensions in Figure 1 of Plate 8 in the Pope County Geologic Atlas, Part B (Berg, 2006a), and in two dimensions on Figure 2 of this plate as the boundaries between the various layers. These elevation surfaces of aquifers and till layers are GIS grid layers that are used in the GIS grid calculations. The calculations, described below, define recharge surface elevations and the thickness of protective layers overlying the aquifers. The second step for creating the pollution sensitivity maps is to develop a simplified three-dimensional model that describes how water from precipi- tation, which first infiltrates the surficial aquifers, can directly recharge portions of the first underlying aquifer and, indirectly, portions of deeper aquifers. The central concept of this process is focused (relatively rapid) recharge. In focused recharge, portions of the aquifers overlap and are connected by complex three-dimensional pathways that allow surface water to penetrate into even the deepest mapped aquifers in some areas. The sensi- tivity model for the buried aquifers uses this idea by dividing this focused recharge into discreet surfaces at the base of each aquifer, which are called recharge surfaces (Berg, 2006b). Each buried aquifer receives focused recharge from the base of the overlying aquifer if the confining layer sepa- rating those aquifers is thin or absent. For the purposes of this model and the process of determining the elevations of the recharge surfaces, “thin” is considered to be 10 feet or less. The vertical recharge path of water for a stack of aquifers typical of Pope and Douglas counties is shown in Figure 2. That figure shows a gener- alized cross section of the principal aquifers mapped in the eastern portion of the study area. Similar stacks of different aquifer combinations exist throughout the study area. The vertical path of water from precipitation at the land surface to buried aquifers crosses recharge surfaces of the buried aquifers. On Figure 2, the recharge surfaces are labeled 1 (generally shallow), 2 (generally intermediate depth), and 3 (generally deep). In this conceptual model, all the recent recharge water enters the buried aquifer system (pink arrow) at recharge surface 1 (red dotted line). In thick sand and gravel areas, the generally shallow recharge surface 1 is at the base of the sand and gravel. Where little or no sand or gravel exists at the surface, recharge surface 1 is the same as the land surface. If the protective, low- permeability layer (till) between the base of recharge surface 1 and the top of the underlying buried aquifer is 10 feet or less, recent recharge water infiltrates to the next underlying aquifer (pink arrow) and moves downward to recharge surface 2 (black dotted line). Where no OT aquifer exists in eastern Pope and Douglas counties, recharge surface 2 is the same as recharge surface 1. If the same criteria are applied at recharge surface 2 (underlying protective layer thickness of 10 feet or less), recent or mixed water (split pink and green arrow) infiltrates to the next underlying aquifer and so on until a limited amount of recent or mixed water reaches recharge surface 3 for the deepest aquifer. Just as the aquifer and till layer surfaces were created as elevation grid layers, the recharge surfaces were also created in this same GIS file format. Each recharge surface was produced through a series of GIS calculations starting with the land surface elevation grid and proceeding stepwise downward to the top of aquifer 1 or the lowest mapped aquifer. With each succeeding step, the deepest portion of the recharge surface becomes progressively smaller, thereby mimicking a general reduc- tion of recharge with depth that occurs in the natural system. The calculated elevation surfaces for all the aquifers, till layers, and recharge surfaces are used in the third step to generate pollution sensitivity maps for each buried aquifer. In the final step of the sensitivity evaluation, the thickness of the protective till that covers each aquifer is calculated and a sensitivity rating is applied. The sensitivity of the aquifer is inversely proportional to the thickness of that protective layer. The protective layer thickness is calculated by subtracting the elevation of the top of the aquifer from the elevation of the adjacent overlying recharge surface. Figure 3 shows the model for interpreting the pollution sensitivity of the buried aqui- fers according to the calculated protective layer thickness. The resulting pollution sensitivity evaluations for each buried aquifer (LG, OT, CW, aqui- fer 1, and western aquifer) are shown on Figures 4, 5, 6, 7, and 8, respec- tively. EVALUATION OF BURIED AQUIFER SENSITIVITY MAPS The results of a valid pollution sensitivity model should generally correspond to the distribution of ground-water residence time indicators. The most important indicators for the buried aquifers were the values and spatial characteristics of tritium in collected ground-water samples. In general, the recent and mixed tritium values should correspond to areas of very high to low sensitivity, whereas, the vintage values should correspond to areas of low to very low sensitivity. The carbon-14 residence time values from collected ground-water samples were also useful for corroborating sensitivity for portions of the buried aquifers that have a predicted very low sensitivity. The chloride to bromide ratios as an anthropogenic indicator of recent industrial age activity were useful evidence of recent water infiltra- tion and an evaluation tool for areas with very high to low pollution sensitiv- ity classifications. The distribution of chemical constituents in ground water can help establish ground-water movement. Chemical data such as tritium and carbon-14 are used to estimate ground-water residence time or age, and high ratios of chloride to bromide (Cl/Br) indicate anthropogenic (human- created) influence on ground water (Berg, 2006b). These chemical data can be indicators of ground-water recharge and movement. A map of the potentiometric surface can also help portray ground-water movement. A potentiometric surface is defined as “a surface that represents the level to which water will rise in a tightly cased well (Fetter, 1988). The potentiometric surface of a confined aquifer (aquifer under pressure) occurs above the top of an aquifer where an overlying confining (low-permeability) layer exists. Static (nonpumping) water-level data from the County Well Index and measurements by personnel from the Department of Natural Resources were plotted and contoured to create the potentiometric contour maps. Low-elevation areas on the potentiometric surface that could be above the coincident surface-water bodies may indicate discharge areas; when combined with other information sources, high-elevation areas on the poten- tiometric surface can be identified as important recharge areas. Ground water moves from higher to lower potentiometric elevations perpendicular to the potentiometric elevation contours (flow directions shown as arrows). LG aquifer. Of the 16 ground-water samples collected from the LG aquifer that were analyzed for tritium or exhibited elevated Cl/Br concentra- tions, all but a few samples had values that matched the expected range of sensitivity classifications (Figure 4). Two exceptions were elevated Cl/Br values in samples taken from wells located in eastern Grant County, south- west of Hoffman. Both locations are near an unnamed tributary of the Pomme de Terre River, which could have created a pathway for surface infiltration to the LG aquifer in that area. OT aquifer. Figure 5 shows good agreement between the tritium age of samples from the OT aquifer and corresponding pollution sensitivity classi- fications. Thirty-three ground-water samples collected from this aquifer were analyzed for tritium or exhibited elevated Cl/Br ratios. All three samples with recent tritium values, which were located in Pope County, occurred in areas mapped with moderate to very high pollution sensitivity ratings. The 13 samples with vintage tritium values were located in areas with very low sensitivity classifications. One sample with a vintage value, found in Traverse County southeast of Wheaton, had a carbon-14 value of 6000 years (Plate 5, left side of cross-section D–D’). Five samples with mixed tritium values were located in areas with low to very high sensitivity. One mixed tritium value in north-central Stevens County just west of Don- nelly and a nearby elevated Cl/Br value are associated with a very low sensi- tivity area. However, these samples were collected from locations downgra- dient of Lundberg Lake, which is a possible pathway for surface-water infiltration. Two other elevated Cl/Br values in Stevens County (east of Chokio and north of Hancock) also are associated with a very low sensitivity area. These locations are downgradient from small surface-water bodies that may have acted as infiltration pathways. Three elevated Cl/Br values in the Hoffman area, west of the Chippewa River in eastern Grant County (left of center, cross-section C–C’), appear to be the result of lateral migration of anthropogenic chloride from the Chippewa River. CW aquifer. Figure 6 also shows good agreement between ground- water residence time indicators and pollution sensitivity classifications for the CW aquifer with a few exceptions. Fifty-three ground-water samples collected from this aquifer were analyzed for tritium or exhibited elevated Cl/Br values. All 28 of the samples with vintage tritium are associated with areas rated as low to very low sensitivity except for one sample in eastern Pope County near Grove Lake, an area rated as high sensitivity. Five of the vintage samples were analyzed for carbon-14 age with values ranging from 100-year-old ground water collected west of Lake Swenoda in eastern Pope County to a 1700-year-old ground water collected west of Kensington in southeastern Grant County (center of cross-section D–D’). Fifteen of the 53 samples from the CW aquifer had mixed tritium values. Four samples with mixed values and three with elevated Cl/Br values are associated with very low sensitivity areas, which is not the expected sensitivity classification. Some of these mixed values and some of the elevated Cl/Br values that seem inconsistent with the sensitivity model are near or possibly downgradient of high-sensitivity areas, which may be the source of mixed water that moved laterally through the CW aquifer to the sample locations. One of the mixed value samples (from west of Sedan along the East Branch of the Chippewa River in Pope County) is associated with an area rated as very high pollution sensitivity. This valley may be a discharge area for buried aquifers. The mixed tritium value of the ground-water sample may have resulted from deep, upward-moving vintage water mixing with near-surface recent water. Seven samples from the CW aquifer had recent tritium values. Six samples with recent values were located in Pope County. Two samples were collected in Glacial Lakes State Park and are associated with high- sensitivity areas, which is consistent with the recent tritium values. The remaining recent tritium samples were collected from areas west of the Chippewa River, near Starbuck, north of Lake Linka and west of Lake Johanna. These sample sites are near and possibly downgradient of high- sensitivity areas that may be the source of the recent water through lateral migration. Aquifer 1. Most of the 71 samples collected from this aquifer for tritium analysis had vintage or mixed tritium values. These results are consistent with the relatively protected geologic setting of this aquifer. All samples with vintage age are associated with areas rated as very low sensi- tivity. Eight of the vintage samples were also analyzed for carbon-14 age. Seven of the carbon-14 samples had ages in the 1000- to 3000-year-old range, and a 100-year-old sample came from the eastern portion of the Belgrade-Glenwood sand plain. All eight carbon-14 samples are associated with areas of very low sensitivity. Most samples with mixed tritium values from aquifer 1 are associated with areas of low to very low sensitivity. Eight of these samples were located in eastern or northeastern Pope County and southeastern Douglas County (right side of cross-section C–C’) near moderate to high sensitivity areas that may have been the source of mixed water moving laterally to the sampling locations. Four mixed value samples (three located in southeastern Pope County and one located near the center of the Pope County east of Lake Jennum) have no apparent source of mixed water. The origin of these tritium values cannot be determined using the existing data. One sample with a vintage tritium value was located west of Carlos in Douglas County and is associated with a high sensitivity area in the Long Prairie River valley. It may have a similar setting to the sample from the CW aquifer described in the previous section. This valley may be a discharge area for buried aquifers. The mixed tritium value may have resulted from deep, upward-moving vintage water mixing with near-surface recent water. Most samples with recent tritium values from aquifer 1 occurred in the Alexandria area. Seven of the 10 recent values in the Alexandria area are clustered southeast of Lake Darling in areas rated as low or very low sensi- tivity. A couple possible source locations for lateral migration of recent water exist in this area. Three of the 10 samples with recent tritium values are located inside the south portion of the Alexandria municipal boundaries, west of Lake Burgan. These three ground-water sampling locations are downgradient from possible source locations of recent water to the south. Two samples with recent tritium values that occurred near the northern edge of Lake Carlos are also both are associated with very low sensitivity areas. These occurrences are difficult to explain with existing information and may be the result of conditions beyond the project area. A sample with recent tritium values located southeast of Sedan in Pope County was consistent with the low to moderate pollution sensitivity classification at that location. Western aquifer. Seven samples collected from the western aquifer were analyzed for tritium or exhibited elevated Cl/Br values. Two of the samples, which are associated with very low sensitivity areas in the south- western portion of the study area in Big Stone County, did not contain detectable concentrations of tritium, indicating vintage residence time conditions. Both samples were also analyzed for carbon-14 with ages rang- ing from 200 years to 3000 years. The locations of the four samples with elevated Cl/Br values were scattered across the western portion of the study area in areas associated with very low sensitivity and cannot be explained with existing information. REFERENCES CITED Berg, J.A., 2006a, Hydrogeologic cross sections [Plate 8], in Geologic Atlas of Pope County, Minnesota: St. Paul, Minnesota Department of Natural Resources, County Atlas Series, C–15, Part B, Scale 1:150,000. ________, 2006b, Sensitivity to pollution of the buried aquifers [Plate 9], in Geologic Atlas of Pope County, Minnesota: St. Paul, Minnesota Department of Natural Resources, County Atlas Series, C–15, Part B, Scale 1:150,000. Fetter, C.W., 1988, Applied hydrogeology (2d ed.): Columbus, Ohio, Merrill, 592 p. Geologic Sensitivity Workgroup, 1991, Criteria and guidelines for assessing geologic sensitivity of ground water resources in Minnesota: St. Paul, Minnesota Department of Natural Resources, Division of Waters, 122 p. 5 0 1 2 3 4 5 10 15 20 KILOMETERS 5 0 1 2 3 4 5 10 15 MILES COMPILATION SCALE 1:100 000 SCALE 1:250 000 RHA-6 RHA-5 RHA-1 RHA-4 RHA-2 RHA-3 RHA-1 Anoka Sand Plain RHA-2 Southwestern Minnesota RHA-3 Southern Red River Valley RHA-4 Upper Minnesota River Basin RHA-5 Otter Tail Area RHA-6 Traverse–Grant Area INDEX OF REGIONAL HYDROGEOLOGIC ASSESSMENTS IN MINNESOTA

REGIONAL HYDROGEOLOGIC ASSESSMENT TRAVERSE GRANT … · ed e e e los Lundberg e Harstad Slough ood e kl es k e ud e Clear e Gorder e Flax e omme de erre es e us vils e a e w Maple

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Page 1: REGIONAL HYDROGEOLOGIC ASSESSMENT TRAVERSE GRANT … · ed e e e los Lundberg e Harstad Slough ood e kl es k e ud e Clear e Gorder e Flax e omme de erre es e us vils e a e w Maple

Big Stone LakeState Park

27

75

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75

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T. 123 N.

T. 126 N.

R. 43 W.R. 44 W.R. 45 W.R. 46 W.R. 47 W.R. 48 W.

R. 43 W.R. 44 W.R. 45 W.R. 46 W.R. 47 W.

T. 127 N.

T. 128 N.

T. 129 N.

Norcross

Herman

Donnelly

AlbertaChokio

Johnson

Clinton

BarryBeardsley

Dumont

Wheaton

Graceville

RoundLake

IslandLake

FishLake

LundbergLake

BarrettLake

CottonwoodLake

NiemacklLakes Werk

Lake

OhlsrudLake

Big Lake

Mud

Lake

LannonLake

EastToquaLake

WestToquaLake

GravelLake

ClearLake

GorderLake

FlaxLake

LakeHattie

NorthRothwellLake

BarryLake

Lake Tr

averse

Graham Lake

River

Mustin

ka

Boi

s d

e S

ioux

Riv

er

Twel

vem

ileC

reek

45°45'

46°00'

96°00'96°15'96°30'

96°30' 96°15' 96°00'S

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BIG STONE COUNTYTRAVERSE COUNTY

BIG

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Glacial LakesState Park

Lake CarlosState Park

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79

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55104

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T. 123 N.

T. 124 N.

T. 125 N.

T. 126 N.

R. 40 W. R. 39 W. R. 38 W. R. 37 W. R. 36 W.R. 41 W.

R. 40 W. R. 39 W. R. 38 W. R. 37 W. R. 36 W.R. 41 W.R. 42 W.

T. 127 N.

T. 128 N.

T. 129 N.

Carlos

Alexandria

Nelson

Westport

Sedan

Lowry

Farwell

Kensington

Hoffman

Barrett

Elbow Lake

Hancock

Villard

Long Beach

Cyrus Starbuck

Glenwood

Osakis

IslandLake

BarrettLake Thompson

Lake

ElkLake

EllingsonLake

PetersonLake

HjermenrudLake

Red RockLake

SolbergLake

Stowe Lake

QuamLake

EngLake

FreebornLake

LakeMary

Lobster Lake

Lake Williams

CrookedLake

Elk Lake

LakeCarlos

Pomme deTerreLakes

LakeCyrus

DevilsLake

ChippewaLake

LakeAndrew

MapleLake

CliffordLake

LakeOscar

LakeThorstad

LakeLatoka

LakeMina

LakeDarling

LakeLeHomme Dieu

LakeVictoria

LakeGeneva

LakeIdaLong

Lake

JennieLake

AldrichLake

DavidsonLake

AlbertLake

LakeCharlotte

MooreLake

LongLake

HanseLake

HansonLake

SwanLake

LakeOsakis

SmithLake

Herberger Lake

KuntzLake

PageLake

PatchenLake

Lake RenoLevenLake

MarluLake

GroveLake

SwenodaLake

GooseLake

ScandinavianLake

GilchristLake

LakeLinka

RasmusonLake

Lake Minnewaska StateLake

JorgensonLake

LarsonLake

ChristophersonLake

MudLake

PelicanLake

RoundLake

SwanLake

VillardLake

AmeliaLake

AnnLake

JohnLake

PikeLake

LybeckLake

McIverLake

EricksonLake

EdwardsLake

NelsonLake

LakeHanson

LakeBen

GilbertsonLake

AliceLake

LakeJohanna

LakeSimon

WestportLake

Lake Emily

WollanLake

MalmedalLake

IrgensLake

Little

Riv

er

Chi

ppew

aR

iver

Eas

tB

ranc

hR

iver

Chi

ppew

a

Chi

ppew

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45°30'

95°15'95°30'

95°45' 95°30' 95°15'

45°45'

46°00'

95°45'

96°00'

DOUGLAS COUNTYPOPE COUNTY

DO

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CO

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AN

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STEVENS COUNTYGRANT COUNTY

PO

PE

CO

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Gilchrist

Brandon

Riv

er

Long

Prai

rie

LakeBurgan

Glacial LakesState Park

Lake CarlosState Park

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T. 123 N.

T. 124 N.

T. 125 N.

T. 126 N.

R. 40 W. R. 39 W. R. 38 W. R. 37 W. R. 36 W.R. 41 W.R. 42 W.R. 43 W.

R. 40 W. R. 39 W. R. 38 W. R. 37 W. R. 36 W.R. 41 W.R. 42 W.R. 43 W.

T. 127 N.

T. 128 N.

T. 129 N.Carlos

Alexandria

Nelson

Westport

Sedan

Lowry

Farwell

Kensington

Hoffman

Barrett

Elbow Lake

Donnelly

Hancock

Alberta

Morris

Villard

Long Beach

CyrusStarbuck

Glenwood

Osakis

RoundLake

IslandLake

LongLake

CormorantLake

BarrettLake Thompson

Lake

ElkLake

EllingsonLake

PetersonLake

HjermenrudLake

Red RockLake

SolbergLake

Stowe Lake

QuamLake

EngLake

FreebornLake

LakeMary

Lobster Lake

Lake Williams

CrookedLake

Elk Lake

LakeCarlos

LundbergLake

HarstadSlough

CottonwoodLake

NiemacklLakes Werk

Lake

OhlsrudLake

ClearLake

GorderLake

FlaxLake

Pomme deTerreLakes

LakeCyrus

DevilsLake

ChippewaLake

LakeAndrew

MapleLake

CliffordLake

LakeOscar

LakeThorstad

LakeLatoka

LakeMina

LakeDarling

LakeLeHomme Dieu

LakeVictoria

LakeGeneva

LakeIdaLong

Lake

JennieLake

AldrichLake

DavidsonLake

AlbertLake

EideLake

Wintermute Lake

LakeCharlotte

MooreLake

LongLake

HanseLake

HansonLake

SwanLake

LakeHattie

LakeOsakis

SmithLake

Herberger Lake

KuntzLake

CrystalLake

PageLake

PatchenLake

Lake RenoLevenLake

GroveLake

SwenodaLake

GooseLake

ScandinavianLake

GilchristLake

LakeLinka

RasmusonLake

Lake Minnewaska StateLake

JorgensonLake

LarsonLake

ChristophersonLake

MudLake

PelicanLake

RoundLake

SwanLake

VillardLake

AmeliaLake

AnnLake

JohnLake

PikeLake

LybeckLake

McIverLake

EricksonLake

EdwardsLake

NelsonLake

LakeHanson

LakeBen

GilbertsonLake

AliceLake

LakeJohanna

LakeSimon

Lake Emily

WollanLake

MalmedalLake

IrgensLake

Little

Riv

er

Terr

e

Riv

er

Chi

ppew

aR

iver

Pomme de

Eas

tB

ranc

hR

iver

Chi

ppew

a

Chi

ppew

a

45°30'

95°15'95°30'

95°45' 95°30' 95°15'

45°45'

46°00'

95°45'96°00'

96°00'

DOUGLAS COUNTYPOPE COUNTY

DO

UG

LAS

CO

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STEVENS COUNTYGRANT COUNTY

PO

PE

CO

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Gilchrist

Brandon

Riv

er

Long Prairie

LakeBurgan

Glacial LakesState Park

Lake CarlosState Park

Big Stone LakeState Park

27

75

28

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114

29

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27

75

27

9

9

59

27

27

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55

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59

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55104

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T. 123 N.

T. 124 N.

T. 125 N.

T. 126 N.

R. 40 W. R. 39 W. R. 38 W. R. 37 W. R. 36 W.

T. 124 N.

T. 123 N.

T. 125 N.

T. 126 N.

R. 41 W.R. 42 W.R. 43 W.R. 44 W.R. 45 W.R. 46 W.R. 47 W.R. 48 W.

R. 49 W.

R. 40 W. R. 39 W. R. 38 W. R. 37 W. R. 36 W.R. 41 W.R. 42 W.R. 43 W.R. 44 W.R. 45 W.R. 46 W.R. 47 W.

T. 127 N.

T. 128 N.

T. 129 N.

T. 127 N.

T. 128 N.

T. 129 N.

Carlos

Alexandria

Nelson

Westport

Sedan

Lowry

Farwell

Kensington

Hoffman

Barrett

Elbow Lake

Norcross

Herman

Donnelly

Hancock

AlbertaChokio

Johnson

Clinton

BarryBeardsley

Browns Valley

Dumont

Morris

Wheaton

Villard

Graceville

Long Beach

Cyrus Starbuck

Glenwood

Osakis

RoundLake

IslandLake

LongLake

CormorantLake

BarrettLake

ThompsonLake

ElkLake

EllingsonLake

PetersonLake

Red RockLake

SolbergLake

Stowe Lake

QuamLake

EngLake

FreebornLake

LakeMary

Lobster Lake

Lake Williams

CrookedLake

Elk Lake

LakeCarlos

FishLake

LundbergLake

HarstadSlough

BarrettLake

CottonwoodLake

NiemacklLakes Werk

Lake

OhlsrudLake

Big Lake

Big S

tone Lake

Mud

Lake

LannonLake

EastToquaLake

WestToquaLake

GravelLake

ClearLake

GorderLake

FlaxLake

Pomme deTerreLakes

LakeCyrus

DevilsLake

ChippewaLake

LakeAndrew

MapleLake

CliffordLake

LakeOscar

LakeThorstad

LakeLatoka

LakeMina

LakeDarling

LakeLeHomme Dieu

LakeVictoria

LakeGeneva

LakeIdaLong

Lake

JennieLake

AldrichLake

DavidsonLake

AlbertLake

EideLake

Wintermute Lake

LakeCharlotte

MooreLake

LongLake

HanseLake

HansonLake

SwanLake

LakeHattie

NorthRothwellLake

BarryLake

LakeOsakis

SmithLake

Herberger Lake

KuntzLake

CrystalLake

PageLake

PatchenLake

Lake Tr

averse

Graham Lake

Lake RenoLevenLake

MarluLake

GroveLake

SwenodaLake

GooseLake

ScandinavianLake

GilchristLake

LakeLinka

RasmusonLake

Lake Minnewaska StateLake

JorgensonLake

LarsonLake

ChristophersonLake

MudLake

PelicanLake

RoundLake

SwanLake

VillardLake

AmeliaLake

AnnLake

JohnLake

PikeLake

McIverLake

EricksonLake

EdwardsLake

NelsonLake

LakeHanson

LakeBen

GilbertsonLake

AliceLake

LakeJohanna

LakeSimon

WestportLake

Lake Emily

WollanLake

MalmedalLake

IrgensLake

Little

Riv

er

Terr

e

Riv

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Chi

ppew

aR

iver

River

Pomme de

Mustin

ka

Eas

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Chi

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45°30'

95°15'95°30'

95°45' 95°30' 95°15'

45°30'

45°45' 45°45'

46°00'46°00'

95°45'96°00'96°15'96°30'

96°30' 96°15' 96°00'

ST

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BIG STONE COUNTYTRAVERSE COUNTY

BIG

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S C

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DOUGLAS COUNTYPOPE COUNTY

DO

UG

LAS

CO

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Y

STEVENS COUNTYGRANT COUNTY

PO

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UN

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ST

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S C

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Gilchrist

Brandon

Riv

er

Long Prairie

LakeBurgan

9

9

59

27

27

55

55

54

79

59

59

28

R. 41 W.R. 42 W.R. 43 W.

R. 41 W.R. 42 W.R. 43 W.

Hoffman

Barrett

Elbow Lake

Donnelly

Hancock

Alberta

Morris

Cyrus

RoundLake

IslandLake

LongLake

CormorantLake

BarrettLake

ThompsonLake

ElkLake

EllingsonLake

PetersonLake

HjermenrudLake

SolbergLake

FishLake

LundbergLake

HarstadSlough

BarrettLake

CottonwoodLake

NiemacklLakes Werk

Lake

OhlsrudLake

Big Lake

ClearLake

GorderLake

FlaxLake

Pomme deTerreLakes

LakeCyrus

DavidsonLake

AlbertLake

EideLake

Wintermute Lake

LakeCharlotte

MooreLake

LongLake

HanseLake

HansonLake

SwanLake

LakeHattie

CrystalLake

PageLake

PatchenLake

Graham Lake

Terr

e

Riv

er

Pomme de

95°45'

95°45'96°00'

96°00'

DO

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LAS

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AN

T C

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STEVENS COUNTYGRANT COUNTY

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Big Stone LakeState Park

28

T. 124 N.

T. 123 N.

R. 48 W.

R. 49 W. Beardsley

Browns Valley

Big S

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45°30'

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6000

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STATE OF MINNESOTADEPARTMENT OF NATURAL RESOURCESDIVISION OF WATERS

REGIONAL HYDROGEOLOGIC ASSESSMENTRHA–6, PART B, PLATE 6 OF 6

Sensitivity to Pollution of the Buried Aquifers

SENSITIVITY TO POLLUTIONOF THE BURIED AQUIFERS

By

James A. Berg

2008

REGIONAL HYDROGEOLOGIC ASSESSMENTTRAVERSE–GRANT AREA, WEST-CENTRAL MINNESOTA

Caution: The information on these maps is a generalized interpretation of the sensitivity of ground water to contamination. The maps are intended to be used for resource protection planning and to help focus the gathering of information for site-specific investigations.

FIGURE 1. Geologic sensitivity rating as defined by vertical travel time (Geologic Sensitivity Workgroup, 1991). Ratings are based on the time range required for water at or near the surface to travel vertically into the ground water of interest or a pollution sensitivity target. Tritium and carbon-14 studies indicate the relative ages of ground water.

GROUND-WATER TRAVEL TIME, IN LOG10 HOURS

0 1 2 3 4 5 6 7

Time range for tritium studies

SE

NS

ITIV

ITY

RAT

ING

Time range forcarbon-14studies

Hour Day Week Month Year Decade Century

Very Low

Moderate

Very High

High

Low

FIGURE 3. Pollution sensitivity rating matrix. Pollution sensitivity is inversely proportional to the thickness of a protective layer between the top of the aquifer and the nearest overlying recharge surface. Any buried aquifer with less than a 10-foot-thick protective layer between it and an overlying recharge surface is rated very high sensitivity because there is little fine-grained material to increase the time of travel. A thicker overly-ing protective layer provides additional protection to the aquifer, and sensitivity ratings are determined based on the thickness of this layer.

Thickness of protective layer between the aquifer and the nearest overlying recharge surface (in feet)

VH H M L VL

0 to 10 10 to 20 20 to 30 30 to 40 Greaterthan 40

Static (nonpumping) water-level data.

MAP EXPLANATION

FIGURE 2. Generalized cross section showing recharge concepts for buried aquifers considered in the sensitivity evaluations. In this conceptual model of the eastern part of the study area, all recent recharge enters the buried aquifer system at recharge surface 1 (red dotted line). Recharge surface 1 is considered to be at the land surface where till is present, at the bottom of surficial sand deposits and at the bottom of surface water bodies where surficial sand is not present. If less than 10 feet of fine-grained sediment (clay or till) exists between recharge surface 1 and the shallowest underlying buried aquifer, then recent recharge is assumed to move to the bottom of that aquifer to form recharge surface 2. The process and criteria are repeated stepwise for deeper aquifers (recharge surface 3).

If shown, ground-water age in years, estimated by carbon-14 isotope analysis.

2000

Map symbols and labels

If shown, nitrate as nitrogen concentration equals or exceeds 3 parts per million.

6.08

Sensitivity ratings

Estimated vertical travel time for water-borne contaminants to enter an aquifer (pollution sensitivity target).

Very High—Hours to months

High—Weeks to years

Moderate—Years to decades

Low—Decades to a century

Very Low—A century or more

VH

H

M

L

VL

The DNR Information Center

Twin Cities: (651) 296-6157Minnesota toll free: 1-888-646-6367Telecommunication device for the hearing impaired (TDD): (651) 296-5484TDD Minnesota toll free: 1-800-657-3929DNR web site: http://www.dnr.state.mn.us

This information is available in alternative format on request.

Equal opportunity to participate in and benefit from programs of the Minnesota Department of Natural Resources is available regardless of race, color, national origin, sex, sexual orientation, marital status, status with regard to public assistance, age, or disability. Discrimination inquiries should be sent to Minnesota DNR, 500 Lafayette Road, St. Paul, MN 55155-4031, or the Equal Opportunity Office, Department of the Interior, Washington, DC 20240.

© 2008 State of Minnesota,Department of Natural Resources, and theRegents of the University of Minnesota.

This map was compiled and generated using geographic information systems (GIS) technology. Digital data products, including chemistry and geophysical data, are available from DNR Waters at http://www.dnr.state.mn.us/waters.This map was prepared from publicly available information only. Every reasonable effort has been made to ensure the accuracy of the factual data on which this map interpretation is based. However, the Department of Natural Resources does not warrant the accuracy, completeness, or any implied uses of these data. Users may wish to verify critical information; sources include both the references here and information on file in the offices of the Minnesota Geological Survey and the Minnesota Department of Natural Resources. Every effort has been made to ensure the interpretation shown conforms to sound geologic and cartographic principles. This map should not be used to establish legal title, boundaries, or locations of improvements.Base modified from Minnesota Geological Survey, Traverse–Grant Area Regional Hydrogeologic Assessment, Part A, 2006.Project data compiled from 2004 to 2007 at a scale of 1:100,000. Universal Transverse Mercator projection, grid zone 15, 1983 North American datum. Vertical datum is mean sea level.GIS and cartography by Jim Berg and Greg Massaro. Edited by Nick Kroska.

ExplanationRecent ground-waterrecharge

Recent or mixedground-water recharge

Recharge surface 1(generally shallow)

Recharge surface 2(generally intermediate)

Recharge surface 3(generally deep)

Aquifer 1

CW aquifer

OT aquiferOtter Tail River group

Crow Wing River group

Browerville formation and other unnamed tills

LowerGooseRiver group

Surficial aquifer

General direction of ground-water flow.

Body of water.Ice margin.

Line of cross section.

Potentiometric contour line. Contour interval is 20 feet.

Ground-water recharge from overlying surficial aquifer to buried aquifer.

Ground-water leakage through multiple aquifers and fine-grained layers.

Lateral ground-water flow.Ground-water discharge from a buried aquifer to surface-water body.

Infiltration through a thin layer of overlying, fine-grained material to an underlying aquifer.

Unknown source of recent or mixed ground water.

Ground-water leakage from an overlying buried aquifer to an underlying buried aquifer.

FIGURE 4. LG aquifer—pollution sensitivity and potentiometric surface. The limited-extent LG aquifer in the central and southwestern portion of the study area mostly has very low pollution sensitivity, except where a thin layer of fine-grained material covers the aquifer. This figure shows good agreement between the portions of this aquifer where the sensitivity model

predicts very low sensitivity and where vintage tritium values occur. Mixed tritium values and most elevated Cl/Br values occur in areas modeled as low to moderate sensitivity. Except for a few locations near the Pomme de Terre River, the directions of regional ground-water flow are generally to the west and southwest.

FIGURE 5. OT aquifer—pollution sensitivity and potentiometric surface. Moderate to very high pollution sensitivity conditions are common for this aquifer in the eastern portion of the study area where the aquifer is covered by a thin layer of fine-grained material. With a few exceptions, this aqui-fer is shown with very low pollution sensitivity in the western portion of the study area where it is mostly covered by thicker layers of fine-grained material. Discharge to the surficial sand and gravel

aquifers of the Pomme de Terre and Chippewa rivers in the central portions of the study area is prob-ably a common occurrence. All the vintage tritium values occur in locations that were modeled as very low sensitivity. Most mixed and recent values occur in areas modeled as moderate to very high sensitivity. The west and southwest directions of regional ground-water flow are complicated locally by the Pomme de Terre and Chippewa rivers and associated tributaries.

FIGURE 6. CW aquifer—pollution sensitivity and potentiometric surface. The CW aqui-fer is relatively sensitive in eastern Pope and Douglas counties where it is typically the first buried aquifer beneath the sensitive surficial aquifers in that portion of the study area. Smaller sensitive areas exist in other parts of the study area, especially in areas associated with the Pomme de Terre and Chippewa rivers where thick surficial aquifers are present and ground-water leakage from the surficial aquifers to the CW aquifer may be common. Indicators of ground-water residence time generally agree with the pollution sensitivity ratings for the CW aquifer. Most vintage tritium values occur in areas that were modeled

as low to very low sensitivity. Five of these vintage samples were also analyzed for carbon-14 age with values ranging from 100 years to 1700 years. Most occurrences of mixed and recent tritium probably resulted from one of the five leakage mechanisms shown on the figure. A regional ground-water divide in eastern Douglas County and northeastern Pope County splits the ground-water flow directions within this aquifer. East of the divide, flow is to the east; flow west of this divide is generally to the southwest with many local complexities created by discharge to local depressions such as Lake Minnewaska and the valleys of the Pomme de Terre and Chippewa rivers.

FIGURE 7. Aquifer 1—pollution sensitivity and potentiometric surface. This aquifer was mostly rated as low and very low pollution sensitivity. Most areas of moderate and high sensitivity occur at scattered locations in the eastern portion of the study area beneath the Belgrade-Glenwood area aqui-fer and the eastern portion of the CW aquifer. In these more sensitive areas, leakage through multiple aquifers appears to be the most common mecha-

nism. Most of the vintage tritium values occur in areas rated as low or very low sensitivity. Vintage samples analyzed for carbon-14 age had values rang-ing from 100 years to 3000 years. Most of the mixed or recent tritium values that were associated with lower than expected pollution sensitivity ratings occur downgradient from areas of higher sensitivity.

FIGURE 8. Western aquifer—pollution sensitivity and potentiomet-ric surface. The mapped area for this aquifer in the western portion of the study area does not have deep or extensive surficial aquifers and the overlying buried aquifer (mostly the OT aquifer) generally has limited extent and thickness. As a result of those conditions, few direct recharge pathways to the western aquifer exist. The few samples from

this aquifer that were analyzed for tritium were vintage age and all occurred in areas rated as very low sensitivity. Two of the vintage samples from Big Stone County that were also analyzed for carbon-14 age had values of 200 years and 3000 years. Ground water generally flowed to the west with some local exceptions.

DNRWaters

1080

If shown on well symbol, chloride to bromide ratio greater than 175.

Tritium age

Color indicates tritium age of water sampled in well. Recent—Water entered the ground since about 1953 (10 or more tritium units [TU]).

Mixed—Water is a mixture of recent and vintage waters (greater than 1 TU to less than 10 TU).

Vintage—Water entered the ground before 1953 (less than or equal to 1 TU). Well not sampled for tritium, but sampled for chloride and bromide.

Well and buried aquifer symbols

LG aquifer

OT aquifer

CW aquifer

Aquifer 1

Western aquifer

INTRODUCTION

This plate describes the relative sensitivity of the uppermost, buried sand and gravel aquifers in the study area to surface or near-surface releases of contaminants. Sensitivity to pollution is defined as the ease with which a surface contaminant moving with water might travel to and enter a subsur-face water source. The maps are intended to help local units of government protect and manage their ground-water resources. The uppermost, buried sand and gravel aquifers, as shown on Plates 4 and 5, include the generally shallow LG aquifer in the central portion of the study area; the OT aquifer, which is also relatively shallow in the eastern one-third of the study area (most of Pope and Douglas counties); the CW aquifer and aquifer 1, which were mapped only for the eastern two-thirds and half of the study area respectively; and the western aquifer, which was mapped for only the west-ern one-third of the study area. These aquifers are the primary sensitivity targets for the following discussion.

The migration of contaminants in or with water through earth materials is a complex phenomenon that depends on many factors. A regional evalua-tion of sensitivity to contaminants requires some simplifying assumptions. For this report, the permeability factor (the ability of earth materials to trans-mit water) was only evaluated qualitatively. Additionally, this evaluation was based on the assumption of vertical ground-water transport, although horizontal flow dominates in many settings. Finally, the sensitivity ratings are based on vertical travel time of water (Figure 1), not the behavior of specific contaminants.

The surficial aquifers were assumed to be highly or very highly sensi-tive almost everywhere in the study area because these aquifers have little or no laterally extensive protective cover (see Figure 4 on Plate 3). No geochemical data were collected to verify directly the sensitivity of surficial aquifers. The surficial aquifer distribution and thickness, however, are important factors in the following pollution sensitivity evaluation of buried sand and gravel aquifers. They are the primary factors controlling recharge water infiltrating to the buried aquifers.

DEVELOPMENT OF POLLUTION SENSITIVITY MODELAND MAPS OF BURIED AQUIFERS

The goals of the pollution sensitivity modeling and mapping process were to calculate the thickness of protective material overlying each aquifer and interpret protective thickness as different levels of pollution sensitivity. The pollution sensitivity modeling and mapping process has three steps. The first step is mapping and defining the aquifers and low-permeability geologic units (protective layers) as three-dimensional geographic informa-tion system (GIS) surfaces. The second step is representing aquifer recharge as a series of related elevation surfaces that can be used along with the protective layer thickness calculations. The third step is interpreting the protective thickness calculations as pollution sensitivity.

In the first step, the top and bottom elevation surfaces that define aqui-fers and the low-permeability till layers are created as described on Plates 3, 4, and 5. These surfaces are represented in three dimensions in Figure 1 of Plate 8 in the Pope County Geologic Atlas, Part B (Berg, 2006a), and in two dimensions on Figure 2 of this plate as the boundaries between the various layers. These elevation surfaces of aquifers and till layers are GIS grid layers that are used in the GIS grid calculations. The calculations, described below, define recharge surface elevations and the thickness of protective layers overlying the aquifers.

The second step for creating the pollution sensitivity maps is to develop a simplified three-dimensional model that describes how water from precipi-tation, which first infiltrates the surficial aquifers, can directly recharge portions of the first underlying aquifer and, indirectly, portions of deeper aquifers. The central concept of this process is focused (relatively rapid) recharge. In focused recharge, portions of the aquifers overlap and are connected by complex three-dimensional pathways that allow surface water to penetrate into even the deepest mapped aquifers in some areas. The sensi-tivity model for the buried aquifers uses this idea by dividing this focused recharge into discreet surfaces at the base of each aquifer, which are called recharge surfaces (Berg, 2006b). Each buried aquifer receives focused recharge from the base of the overlying aquifer if the confining layer sepa-rating those aquifers is thin or absent. For the purposes of this model and the process of determining the elevations of the recharge surfaces, “thin” is considered to be 10 feet or less.

The vertical recharge path of water for a stack of aquifers typical of Pope and Douglas counties is shown in Figure 2. That figure shows a gener-alized cross section of the principal aquifers mapped in the eastern portion of the study area. Similar stacks of different aquifer combinations exist throughout the study area. The vertical path of water from precipitation at the land surface to buried aquifers crosses recharge surfaces of the buried aquifers. On Figure 2, the recharge surfaces are labeled 1 (generally shallow), 2 (generally intermediate depth), and 3 (generally deep). In this conceptual model, all the recent recharge water enters the buried aquifer system (pink arrow) at recharge surface 1 (red dotted line). In thick sand and gravel areas, the generally shallow recharge surface 1 is at the base of the sand and gravel. Where little or no sand or gravel exists at the surface, recharge surface 1 is the same as the land surface. If the protective, low- permeability layer (till) between the base of recharge surface 1 and the top of the underlying buried aquifer is 10 feet or less, recent recharge water infiltrates to the next underlying aquifer (pink arrow) and moves downward to recharge surface 2 (black dotted line). Where no OT aquifer exists in eastern Pope and Douglas counties, recharge surface 2 is the same as recharge surface 1. If the same criteria are applied at recharge surface 2 (underlying protective layer thickness of 10 feet or less), recent or mixed water (split pink and green arrow) infiltrates to the next underlying aquifer and so on until a limited amount of recent or mixed water reaches recharge surface 3 for the deepest aquifer. Just as the aquifer and till layer surfaces were created as elevation grid layers, the recharge surfaces were also created in this same GIS file format. Each recharge surface was produced through a series of GIS calculations starting with the land surface elevation grid and proceeding stepwise downward to the top of aquifer 1 or the lowest mapped aquifer. With each succeeding step, the deepest portion of the recharge surface becomes progressively smaller, thereby mimicking a general reduc-tion of recharge with depth that occurs in the natural system.

The calculated elevation surfaces for all the aquifers, till layers, and recharge surfaces are used in the third step to generate pollution sensitivity maps for each buried aquifer. In the final step of the sensitivity evaluation, the thickness of the protective till that covers each aquifer is calculated and a sensitivity rating is applied. The sensitivity of the aquifer is inversely proportional to the thickness of that protective layer. The protective layer thickness is calculated by subtracting the elevation of the top of the aquifer from the elevation of the adjacent overlying recharge surface. Figure 3 shows the model for interpreting the pollution sensitivity of the buried aqui-fers according to the calculated protective layer thickness. The resulting pollution sensitivity evaluations for each buried aquifer (LG, OT, CW, aqui-fer 1, and western aquifer) are shown on Figures 4, 5, 6, 7, and 8, respec-tively.

EVALUATION OF BURIED AQUIFER SENSITIVITY MAPS

The results of a valid pollution sensitivity model should generally correspond to the distribution of ground-water residence time indicators. The most important indicators for the buried aquifers were the values and spatial characteristics of tritium in collected ground-water samples. In general, the recent and mixed tritium values should correspond to areas of very high to low sensitivity, whereas, the vintage values should correspond to areas of low to very low sensitivity. The carbon-14 residence time values from collected ground-water samples were also useful for corroborating sensitivity for portions of the buried aquifers that have a predicted very low sensitivity. The chloride to bromide ratios as an anthropogenic indicator of recent industrial age activity were useful evidence of recent water infiltra-tion and an evaluation tool for areas with very high to low pollution sensitiv-ity classifications.

The distribution of chemical constituents in ground water can help establish ground-water movement. Chemical data such as tritium and carbon-14 are used to estimate ground-water residence time or age, and high ratios of chloride to bromide (Cl/Br) indicate anthropogenic (human- created) influence on ground water (Berg, 2006b). These chemical data can be indicators of ground-water recharge and movement.

A map of the potentiometric surface can also help portray ground-water movement. A potentiometric surface is defined as “a surface that represents

the level to which water will rise in a tightly cased well (Fetter, 1988). The potentiometric surface of a confined aquifer (aquifer under pressure) occurs above the top of an aquifer where an overlying confining (low-permeability) layer exists. Static (nonpumping) water-level data from the County Well Index and measurements by personnel from the Department of Natural Resources were plotted and contoured to create the potentiometric contour maps. Low-elevation areas on the potentiometric surface that could be above the coincident surface-water bodies may indicate discharge areas; when combined with other information sources, high-elevation areas on the poten-tiometric surface can be identified as important recharge areas. Ground water moves from higher to lower potentiometric elevations perpendicular to the potentiometric elevation contours (flow directions shown as arrows).

LG aquifer. Of the 16 ground-water samples collected from the LG aquifer that were analyzed for tritium or exhibited elevated Cl/Br concentra-tions, all but a few samples had values that matched the expected range of sensitivity classifications (Figure 4). Two exceptions were elevated Cl/Br values in samples taken from wells located in eastern Grant County, south-west of Hoffman. Both locations are near an unnamed tributary of the Pomme de Terre River, which could have created a pathway for surface infiltration to the LG aquifer in that area.

OT aquifer. Figure 5 shows good agreement between the tritium age of samples from the OT aquifer and corresponding pollution sensitivity classi-fications. Thirty-three ground-water samples collected from this aquifer were analyzed for tritium or exhibited elevated Cl/Br ratios. All three samples with recent tritium values, which were located in Pope County, occurred in areas mapped with moderate to very high pollution sensitivity ratings. The 13 samples with vintage tritium values were located in areas with very low sensitivity classifications. One sample with a vintage value, found in Traverse County southeast of Wheaton, had a carbon-14 value of 6000 years (Plate 5, left side of cross-section D–D’). Five samples with mixed tritium values were located in areas with low to very high sensitivity. One mixed tritium value in north-central Stevens County just west of Don-nelly and a nearby elevated Cl/Br value are associated with a very low sensi-tivity area. However, these samples were collected from locations downgra-dient of Lundberg Lake, which is a possible pathway for surface-water infiltration. Two other elevated Cl/Br values in Stevens County (east of Chokio and north of Hancock) also are associated with a very low sensitivity area. These locations are downgradient from small surface-water bodies that may have acted as infiltration pathways. Three elevated Cl/Br values in the Hoffman area, west of the Chippewa River in eastern Grant County (left of center, cross-section C–C’), appear to be the result of lateral migration of anthropogenic chloride from the Chippewa River.

CW aquifer. Figure 6 also shows good agreement between ground- water residence time indicators and pollution sensitivity classifications for the CW aquifer with a few exceptions. Fifty-three ground-water samples collected from this aquifer were analyzed for tritium or exhibited elevated Cl/Br values. All 28 of the samples with vintage tritium are associated with areas rated as low to very low sensitivity except for one sample in eastern Pope County near Grove Lake, an area rated as high sensitivity. Five of the vintage samples were analyzed for carbon-14 age with values ranging from 100-year-old ground water collected west of Lake Swenoda in eastern Pope County to a 1700-year-old ground water collected west of Kensington in southeastern Grant County (center of cross-section D–D’). Fifteen of the 53 samples from the CW aquifer had mixed tritium values. Four samples with mixed values and three with elevated Cl/Br values are associated with very low sensitivity areas, which is not the expected sensitivity classification. Some of these mixed values and some of the elevated Cl/Br values that seem inconsistent with the sensitivity model are near or possibly downgradient of high-sensitivity areas, which may be the source of mixed water that moved laterally through the CW aquifer to the sample locations. One of the mixed value samples (from west of Sedan along the East Branch of the Chippewa River in Pope County) is associated with an area rated as very high pollution sensitivity. This valley may be a discharge area for buried aquifers. The mixed tritium value of the ground-water sample may have resulted from deep, upward-moving vintage water mixing with near-surface recent water.

Seven samples from the CW aquifer had recent tritium values. Six samples with recent values were located in Pope County. Two samples were collected in Glacial Lakes State Park and are associated with high-sensitivity areas, which is consistent with the recent tritium values. The remaining recent tritium samples were collected from areas west of the Chippewa River, near Starbuck, north of Lake Linka and west of Lake Johanna. These sample sites are near and possibly downgradient of high- sensitivity areas that may be the source of the recent water through lateral migration.

Aquifer 1. Most of the 71 samples collected from this aquifer for tritium analysis had vintage or mixed tritium values. These results are consistent with the relatively protected geologic setting of this aquifer. All samples with vintage age are associated with areas rated as very low sensi-tivity. Eight of the vintage samples were also analyzed for carbon-14 age. Seven of the carbon-14 samples had ages in the 1000- to 3000-year-old range, and a 100-year-old sample came from the eastern portion of the Belgrade-Glenwood sand plain. All eight carbon-14 samples are associated with areas of very low sensitivity.

Most samples with mixed tritium values from aquifer 1 are associated with areas of low to very low sensitivity. Eight of these samples were located in eastern or northeastern Pope County and southeastern Douglas County (right side of cross-section C–C’) near moderate to high sensitivity areas that may have been the source of mixed water moving laterally to the sampling locations. Four mixed value samples (three located in southeastern Pope County and one located near the center of the Pope County east of Lake Jennum) have no apparent source of mixed water. The origin of these tritium values cannot be determined using the existing data. One sample with a vintage tritium value was located west of Carlos in Douglas County and is associated with a high sensitivity area in the Long Prairie River valley. It may have a similar setting to the sample from the CW aquifer described in the previous section. This valley may be a discharge area for buried aquifers. The mixed tritium value may have resulted from deep, upward-moving vintage water mixing with near-surface recent water.

Most samples with recent tritium values from aquifer 1 occurred in the Alexandria area. Seven of the 10 recent values in the Alexandria area are clustered southeast of Lake Darling in areas rated as low or very low sensi-tivity. A couple possible source locations for lateral migration of recent water exist in this area. Three of the 10 samples with recent tritium values are located inside the south portion of the Alexandria municipal boundaries, west of Lake Burgan. These three ground-water sampling locations are downgradient from possible source locations of recent water to the south. Two samples with recent tritium values that occurred near the northern edge of Lake Carlos are also both are associated with very low sensitivity areas. These occurrences are difficult to explain with existing information and may be the result of conditions beyond the project area. A sample with recent tritium values located southeast of Sedan in Pope County was consistent with the low to moderate pollution sensitivity classification at that location.

Western aquifer. Seven samples collected from the western aquifer were analyzed for tritium or exhibited elevated Cl/Br values. Two of the samples, which are associated with very low sensitivity areas in the south-western portion of the study area in Big Stone County, did not contain detectable concentrations of tritium, indicating vintage residence time conditions. Both samples were also analyzed for carbon-14 with ages rang-ing from 200 years to 3000 years. The locations of the four samples with elevated Cl/Br values were scattered across the western portion of the study area in areas associated with very low sensitivity and cannot be explained with existing information.

REFERENCES CITED

Berg, J.A., 2006a, Hydrogeologic cross sections [Plate 8], in Geologic Atlas of Pope County, Minnesota: St. Paul, Minnesota Department of Natural Resources, County Atlas Series, C–15, Part B, Scale 1:150,000.

________, 2006b, Sensitivity to pollution of the buried aquifers [Plate 9], in Geologic Atlas of Pope County, Minnesota: St. Paul, Minnesota Department of Natural Resources, County Atlas Series, C–15, Part B, Scale 1:150,000.

Fetter, C.W., 1988, Applied hydrogeology (2d ed.): Columbus, Ohio, Merrill, 592 p.

Geologic Sensitivity Workgroup, 1991, Criteria and guidelines for assessing geologic sensitivity of ground water resources in Minnesota: St. Paul, Minnesota Department of Natural Resources, Division of Waters, 122 p.

5 01234 5 10 15 20 KILOMETERS

5 01234 5 10 15 MILES

COMPILATION SCALE 1:100 000SCALE 1:250 000

RHA-6

RHA-5

RHA-1

RHA-4

RHA-2

RHA-3

RHA-1 Anoka Sand PlainRHA-2 Southwestern MinnesotaRHA-3 Southern Red River ValleyRHA-4 Upper Minnesota River BasinRHA-5 Otter Tail AreaRHA-6 Traverse–Grant Area

INDEX OF REGIONAL HYDROGEOLOGIC ASSESSMENTSIN MINNESOTA

Justejn Gorder-Devojka Sa Pomorandzama

Justejn Gorder-Devojka Sa Pomorandzama

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Vils presentation of implementing e governance

Vils presentation of implementing e governance

Education
Vils krishna

Vils krishna

Education
Justejn Gorder - Kći Direktora Cirkusa

Justejn Gorder - Kći Direktora Cirkusa

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Probleme der Kriminal- und Sozialprognose Matthias Dose Ärztlicher Direktor der Klinik Taufkirchen (Vils)

Probleme der Kriminal- und Sozialprognose Matthias Dose Ärztlicher Direktor der Klinik Taufkirchen (Vils)

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Patientenbefragung in der Forensik - metrik.de · kbo-Isar-Amper-Klinikum Taufkirchen (Vils) Metrik – Patientenbefragung in der Forensik | Fulda, 29. Februar 2012 | 22 Komplexität:

Patientenbefragung in der Forensik - metrik.de · kbo-Isar-Amper-Klinikum Taufkirchen (Vils) Metrik – Patientenbefragung in der Forensik | Fulda, 29. Februar 2012 | 22 Komplexität:

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Literatura Archeviti - eegtests.files.wordpress.com · biWs rom scodnoda, ra tkivili gubdeboda Tamazis mkerdSi! vin mixvdeboda am tki-vils? biWic ki vera. Tamazi sicocxles wyevlida

Literatura Archeviti - eegtests.files.wordpress.com · biWs rom scodnoda, ra tkivili gubdeboda Tamazis mkerdSi! vin mixvdeboda am tki-vils? biWic ki vera. Tamazi sicocxles wyevlida

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Reit- und Fahrverein Taufkirchen (Vils) e.V ...Reit- und Fahrverein Taufkirchen (Vils) e.V. Zeiteinteilung 13. - 14. Juni 2020 Telefonnummer Meldestelle: 0175/520 96 80 - erreichbar

Reit- und Fahrverein Taufkirchen (Vils) e.V ...Reit- und Fahrverein Taufkirchen (Vils) e.V. Zeiteinteilung 13. - 14. Juni 2020 Telefonnummer Meldestelle: 0175/520 96 80 - erreichbar

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Karen Van Gorder 19 July 2010 Setting Up A Wiki For Collaboration Copyright© 2010 BAE Systems, ITT Defense and Information Solutions, Northrop Grumman

Karen Van Gorder 19 July 2010 Setting Up A Wiki For Collaboration Copyright© 2010 BAE Systems, ITT Defense and Information Solutions, Northrop Grumman

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vorl. Zeiteinteilung Taufkirchen 10.-12.06 · Reit- und Fahrverein Taufkirchen (Vils) e.V. Zeiteinteilung Taufkirchener TurnierTage vom 10. – 12. Juni 2016 Telefonnummer Meldestelle:

vorl. Zeiteinteilung Taufkirchen 10.-12.06 · Reit- und Fahrverein Taufkirchen (Vils) e.V. Zeiteinteilung Taufkirchener TurnierTage vom 10. – 12. Juni 2016 Telefonnummer Meldestelle:

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ZE Taufkirchen III - IV 2017 - meldestelle-bayern.deIII+D+2017_ZE-RPP-P_NEU.pdf · Reit- und Fahrverein Taufkirchen (Vils) e.V. Zeiteinteilung Taufkirchener TurnierTage 2017 Telefonnummer

ZE Taufkirchen III - IV 2017 - meldestelle-bayern.deIII+D+2017_ZE-RPP-P_NEU.pdf · Reit- und Fahrverein Taufkirchen (Vils) e.V. Zeiteinteilung Taufkirchener TurnierTage 2017 Telefonnummer

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VILS 20130208 8315[1] - Startseite » Schweppermannspiele

VILS 20130208 8315[1] - Startseite » Schweppermannspiele

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Gestão empresarial - [A] (col.) - No. 1 - Leonardo Vils - Como motivar sua equipe - Motivação, incentivo e crescimento

Gestão empresarial - [A] (col.) - No. 1 - Leonardo Vils - Como motivar sua equipe - Motivação, incentivo e crescimento

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15. Juli 2012 2012.pdf · Veranstalter und Anmeldung ARGE SKI-TRAIL, Riefweg 2, A-6682 Vils Infotel. +43-676-710 82 49 info@rad-marathon.at 230 km e 2.940 m di dislivello

15. Juli 2012 2012.pdf · Veranstalter und Anmeldung ARGE SKI-TRAIL, Riefweg 2, A-6682 Vils Infotel. +43-676-710 82 49 [email protected] 230 km e 2.940 m di dislivello

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MHS Molecular HIV Surveillance(?) and Community Engagement · 2019. 12. 18. · Dana Van Gorder, Executive Director. Community Consultation and Data 2 Care. The Environment in 2012

MHS Molecular HIV Surveillance(?) and Community Engagement · 2019. 12. 18. · Dana Van Gorder, Executive Director. Community Consultation and Data 2 Care. The Environment in 2012

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kbo-Isar-Amper-Klinikum Taufkirchen (Vils) · 2 q-bericht-iak-kt-2012-140212.doc Qualitätsbericht kbo-Isar-Amper-Klinikum Taufkirche n (Vils) Strukturierter Qualitätsbericht gemäß

kbo-Isar-Amper-Klinikum Taufkirchen (Vils) · 2 q-bericht-iak-kt-2012-140212.doc Qualitätsbericht kbo-Isar-Amper-Klinikum Taufkirche n (Vils) Strukturierter Qualitätsbericht gemäß

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The Lithuanian Partner Visaginas International Languages School - VILS

The Lithuanian Partner Visaginas International Languages School - VILS

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Isar-Amper-Klinikum Klinik Taufkirchen (Vils) · Isar-Amper-Klinikum . Klinik Taufkirchen (Vils) Psychiatrie – Psychotherapie -Psychosomatische Medizin . Akademische Lehreinrichtung

Isar-Amper-Klinikum Klinik Taufkirchen (Vils) · Isar-Amper-Klinikum . Klinik Taufkirchen (Vils) Psychiatrie – Psychotherapie -Psychosomatische Medizin . Akademische Lehreinrichtung

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kbo-Isar-Amper-Klinikum Taufkirchen (Vils) · kbo-Isar-Amper-Klinikum Taufkirchen (Vils) Psychiatrie - Psychotherapie - Psychosomatische Medizin Akademische Lehreinrichtung der …

kbo-Isar-Amper-Klinikum Taufkirchen (Vils) · kbo-Isar-Amper-Klinikum Taufkirchen (Vils) Psychiatrie - Psychotherapie - Psychosomatische Medizin Akademische Lehreinrichtung der …

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Abraham Maslow’s Hierarchy of Needs as it Appears in the Novel Frankenstein A study by Taylor Gorder

Abraham Maslow’s Hierarchy of Needs as it Appears in the Novel Frankenstein A study by Taylor Gorder

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Geschäftsbericht 2018 - VR-Bank Isar-Vils€¦ · Geldanlage – eine Generation weitergedacht. Mit PrivatFonds: Nachhaltig Wussten Sie schon, dass es auch bei der Geldanlage Möglichkeiten

Geschäftsbericht 2018 - VR-Bank Isar-Vils€¦ · Geldanlage – eine Generation weitergedacht. Mit PrivatFonds: Nachhaltig Wussten Sie schon, dass es auch bei der Geldanlage Möglichkeiten

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A High Elevation Aerosol Inlet Modeling Study and Inter-comparison A. Gannet Hallar 1, Ian McCubbin 1, Igor Novosselov 2, Riley Gorder 2, John Ogren 3

A High Elevation Aerosol Inlet Modeling Study and Inter-comparison A. Gannet Hallar 1, Ian McCubbin 1, Igor Novosselov 2, Riley Gorder 2, John Ogren 3

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Sicherung – Therapie – Freiheitiak-kmo.de/fileadmin/user_upload/Flyer_Januar_2015/Forensik_kboIAK... · kbo-Isar-Amper-Klinikum Taufkirchen (Vils) zuständig ist. Lange mußten

Sicherung – Therapie – Freiheitiak-kmo.de/fileadmin/user_upload/Flyer_Januar_2015/Forensik_kboIAK... · kbo-Isar-Amper-Klinikum Taufkirchen (Vils) zuständig ist. Lange mußten

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Københavns Universitet - Akademisk Råd Ordinært …...Timo Minssen (JUR, centerleder) Marianne Nielsen (SCIENCE, HR-centerchef ) Thomas Vils Pedersen (Fælles VIP TR, SCIENCE) Anders

Københavns Universitet - Akademisk Råd Ordinært …...Timo Minssen (JUR, centerleder) Marianne Nielsen (SCIENCE, HR-centerchef ) Thomas Vils Pedersen (Fælles VIP TR, SCIENCE) Anders

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Dakota State University Leading Successful Meetings: Making Minutes Count Presented by: Lynette Molstad Gorder

Dakota State University Leading Successful Meetings: Making Minutes Count Presented by: Lynette Molstad Gorder

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Roadhouse Vils

Roadhouse Vils

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Exchange Student Course Registration Guide! An animated explanation by Eric Carl Van Gorder

Exchange Student Course Registration Guide! An animated explanation by Eric Carl Van Gorder

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Palestra Erick Vils no Café com Franquia da ABF-Rio (Tecnologias Para Alavancar o Franchising)

Palestra Erick Vils no Café com Franquia da ABF-Rio (Tecnologias Para Alavancar o Franchising)

Business
Justejn Gorder SOFIJIN SVET - ROMAN O ISTORIJI FILOZOFIJE

Justejn Gorder SOFIJIN SVET - ROMAN O ISTORIJI FILOZOFIJE

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3.1 ХІМІЧНІ ОПІКИmsvitu.com/pages/medical-books/Vils/R3.pdf · 24 Розділ 3 Травми роннього тіла, особливо якщо стороннє тіло

3.1 ХІМІЧНІ ОПІКИmsvitu.com/pages/medical-books/Vils/R3.pdf · 24 Розділ 3 Травми роннього тіла, особливо якщо стороннє тіло

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