Appendix B Watershed Hydrology/Hydraulics

Appendix B

Watershed Hydrology/Hydraulics XP-SWMM Model Calibration Monitoring Station Rating Curves

Wenck Associates, Inc. 1800 Pioneer Creek Ctr. P.O. Box 249 Maple Plain, MN 55359-0249 (763) 479-4200 Fax (763) 479-4242 E-mail: [email protected]

T:\1676-CLFLWD\01\16 - Reports\REPORT - FINAL-101907\Appendix B\Appendix B XPSWMM Memo.doc

TECHNICAL MEMORANDUM TO: John R. Thene, P.E., Project Manager Wenck Associates, Inc. FROM: Pamela Massaro, P.E., Project Engineer John B. Erdmann, PhD, P.E. DATE: September 18, 2007 SUBJECT: Comfort Lake Forest Lake Watershed District XP-SWMM Model Calibration Description of the XP-SWMM Model The XP-SWMMTM Model (v9.1) is a comprehensive water quantity simulation model for environmental engineering analysis in urban and rural areas from the XP-Software, Inc. The XP-SWMM software is based on the USEPA Storm Water Management Model (SWMM), originally developed for the USEPA between 1969 and 1971 and continually refined for the past 35 years. USEPA SWMM has an extensive history as a tool for analyzing wet-weather issues in watershed systems. XP-SWMM uses the simulation engineers from USEPA SWMM and adds several user enhancements such a graphical user interface. XP-SWMM is a dynamic mechanistic model that can be applied in both single-event and continuous simulations and accounts for all important components of the time-varying rainfall, runoff and flow routing cycle in a watershed. Flow routing can be analyzed for both piped collection systems and natural drainage channel networks. Details of the XP-SWMM solution framework are provided in the XP-SWMM User Manual. The hydrologic simulations are provided in the RUNOFF block of XP-SWMM. The RUNOFF block uses catchments information including area, imperviousness, slope, roughness, overland flow length, depression storage, and Horton Equation & Green-Ampt infiltration parameters to predict time-varying runoff hydrographs. The RUNOFF simulation is driven by user-defined precipitation data. The flow routing simulations are preformed in the HYDRAULICS block of XP-SWMM. HYDRAULICS accepts the time-varying runoff hydrographs from the modeled catchments and routes the flows through the defined channel networks using dynamic wave solution techniques (St Venant equations,) which accounts for backwater conditions. Individual channel reaches and culverts are defined in HYDRAULICS in terms of shape and dimensions of open channels or pipes, slope and roughness. XP-SWMM Modeling Wenck started with the revised CLFLWD's ‘high-flow’ XP-SWMM model for the hydrologic and hydraulic modeling (SRF Consulting Group’s H&H model, May 2005.)

Page 2 of 6 Wenck prepared a memorandum (dated December 21, 2006) summarizing our review of SRF’s existing CLFLWSD XP-SWMM model compared to FEMA standards for floodplain analysis and other accepted practices. SRF responded with an update to their hydrologic/hydraulic report, as well as providing Wenck with updated XP-SWMM model files and GIS files. Hydrologic and Hydraulic Model The hydrologic model (developed by SRF in XP-SWMM RUNOFF) is made of 286 subwatersheds and 41-explicilty modeled open water features in the CLFLWD’s 49 square mile drainage area. The hydraulic model (developed by SRF in XP-SWMM HYDRAULICS) contains nearly 50-miles of open channels and pipes and 134-explicilty modeled flood water storages. SRF’s May 2005 ‘Hydraulic Capacity and Model Calibration Report’ documents the background model building information and ‘high flow’ calibration. Various XP-SWMM model changes were required to ready for predicting non-flood conditions. Inactive RUNOFF Nodes Three RUNOFF subcatchments were disabled; SBL15A, CL05A, CL45B. These were nodes that didn’t have any attributes defined, thus were not generating runoff. Little Comfort Lake In the original SRF model Little Comfort Lake was not an explicitly modeled open water feature. Modifications were made in RUNOFF and HYDRAULICS to incorporate this principal study lake. Birch Lake & School Lake In the original SRF model Birch Lake and School Lake was not explicitly modeled open water features in RUNOFF, but they both are modeled explicitly in HYDRAULICS as storage nodes. Birch Lake and School Lake were not identified as principal study lakes, so XP-SWMM was not modified. The Water Budgets & TP budgets explicitly account for the precipitation and atmospheric TP loading on the lake surfaces. Precipitation XP-SWMM reads the 15-minute precipitation, as monitored by Washington Conservation District. Each subwatershed in RUNOFF was assigned the nearest monitored precipitation record by implementing the Thiessen polygons method. If a lake or subwatershed’s surface area was to be assigned to multiple gages, XP-SWMM assigned the gauge that covered the largest percent of the total area. Changes were made on the 42-explicilty modeled open water features in XP-SWMM RUNOFF so that the rain falling on the open water features was more realistically modeled.

• Create “Lakes” infiltration card. Set 42 (R) subs (#2 Lakes) to Horton’s Infiltration (Fo = 0.001, Fc = 0.0001, α = 0.00139, Maximum Infiltration Rate = 0.000)

Impervious Pervious Depressional Storage (in) 0.0 0.0 Manning’s η 0.014 0.030 Zero Detention (%) 100

• Change Width in (42) (R) block subs (#2 Lakes) to

)(10)/(66.559,43*)()(

ftacresftacresAreaftWidth =

Page 3 of 6 Evaporation St. Paul Campus Climatological Observatory (21-8450-6) monthly pan evaporation (inches) observations from 2003-2006 were converted to lake evaporation using a pan coefficient of 74.5% (Hydrology Guide for Minnesota for CLFLWD.) Then they were adjusted to represent the CLFLWD values for 2003-2006 by the same ratio of mean monthly lake evaporations of St. Paul Campus to CLFLWD from the Hydrology Guide for Minnesota. The St. Paul Campus Climatological Observatory has monthly values for May thru September, and values for April (21-30) and October (1-10.) The Hydrology Guide for Minnesota CLFLWD values were used for mid-autumn, winter and mid-spring (October 11 thru April 20.) Evaporation rates were directly input in XP-SWMM RUNOFF, as reduced monthly values because a special configuration parameter (“HDR_EVAP”) is enabled to allow evaporation to occur at storage nodes in HYDRAULICS to represent lake surface evaporation. The monthly evaporation rates needed to be reduced by evaporation calibration so that the net lake evaporation in XP-SWMM RUNOFF & HYDRAULICS didn’t over estimate the modeled evaporation. Evaporation was calibrated for 2004 (average conditions) at three lake locations; Forest Lake, Bone Lake and Shields Lake. CLFLWD Modeled Evaporation (inches)

2006 2005 2004 2003

Net XP R block Net

XP R block Net

XP R block Net

XP R block

January 0.32 0.31 0.32 0.31 0.32 0.31 0.32 0.31 February 0.31 0.30 0.31 0.30 0.31 0.3 0.31 0.30 March 0.81 0.79 0.81 0.79 0.81 0.79 0.81 0.79 April 2.01 1.95 2.00 1.95 2.51 2.44 2.64 2.57 May 4.25 4.13 3.09 3.01 3.85 3.74 4.22 4.10 June 5.58 5.44 4.91 4.78 4.45 4.33 4.40 4.28 July 6.51 6.34 6.27 6.11 4.71 4.59 4.89 4.76 August 4.07 3.95 4.62 4.48 3.66 3.55 4.86 4.72 September 2.37 2.31 3.47 3.37 3.54 3.44 3.78 3.68 October 2.89 2.81 2.74 2.66 2.79 2.71 2.88 2.79 November 1.33 1.29 1.33 1.29 1.33 1.29 1.33 1.29 December 0.38 0.37 0.38 0.37 0.38 0.37 0.38 0.37 30.84 30.25 28.65 30.82

Groundwater XP-SWMM can be made to model the groundwater interactions, but the interactions must be defined externally, input at recharging/discharging locations, and calibrated. Groundwater discharge and recharge zones were not explicitly modeled in XP-SWMM, but explicitly incorporated into the Water Budgets. The same statement applies to the groundwater interactions from land locked basins. Implicitly, groundwater is modeled in XP-SWMM by calibrating to the cumulative discharge monitored at 2004 monitoring locations.

Page 4 of 6 Initial Conditions HYDRAULICS Flow rates at monitoring locations during spring (2003-2006) were reviewed to define the “typical” spring baseflow conditions for HYDRAULICS. The following average DWFs were input in HYDRAULICS and run for a year (without any precipitation) to allow stead state to be achieved. This ‘hot start’ file aided the model predict the discharge rates in early April 2004.

Monitor ID Model Link "typical"

spring DWF (cfs)

Modeled Hot Start

Flow (cfs)

Percent Difference

SM#1 L115 5 5 0% SM#2 L165 0.3 0.3 0% SM#3 SBL38 out 3.56 3.56 0% SM#4 LLCL-9 7.0 6.92 -1% SM#5 FL63 Out4 1.49 1.49 0% SM#6 L272 12.62 12.62 0% SM#7 CL39 out 15.0 14.77 -2% SM#8 CL54A out 25.0 24.69 -1%

Calibration The model was calibrated to average conditions. 2004 monitoring data was selected as average conditions based on monitoring at the Comfort Lake Outlet. The calibrated 2004 model is a reasonable match to observed discharges, total volume, and water surface levels. Hydraulic Calibration results are presented in the three groups of figures attached to this memorandum.

• The first group of figures compares the model predictions of cumulative volumetric discharge over the monitoring period to monitored data for the monitoring stations (SM1, SM4, SM6, SM7, SM8).

• The second group of figures compares the model predicted discharge rates to monitoring for the monitoring stations (SM1, SM4, SM6, SM7, SM8).

• The third group of figures compares the model predicted water surface elevations to MN DNR lake finder data at Bone Lake, Little Comfort Lake, Shields Lake, Forest Lake and Comfort Lake.

These results were obtained with adjustment to flow monitor specific Horton Infiltration parameters in RUNOFF. Wenck is providing a CD to the District containing additional information documenting SRF's ‘high-flow’ model values (starting) and the final 2004 (average conditions) calibrated values for infiltration. The monitoring data indicates a strong seasonal variance in the Comfort Lake Watershed District that is difficult to model using a simple XP-SWMM modeling approach. Calibrating to cumulative volumetric discharges on a water year time frame allows for the seasonal variability to be accounted for in a general/simple/transparent way that allows a “best-fit” through the water year’s extremes and properly predicts the water year volumes. This calibration approach is also favorable due to the fact that XP-SWMM results is fed into the lake response model (by way of the Water Budget) to evaluate the water quality effect of average annual loads.

Page 5 of 6 The high runoff extreme in the water year is monitored in spring. The winter’s precipitation is stored in the snowpack then released during snowmelt events, usually in the spring, when the ground is frozen. The subwatershed’s percent impervious is effectively increased, under these conditions, and results in a larger runoff volume. It is during these spring runoff events that the ice on the lakes could also be reducing the effective volumes and outlet could be clogged with ice or debris. The low runoff extreme was monitored to occur in late summer, when the hydrologic cycle’s components of plant uptake, infiltration, evaporation, and transpiration are greater influences on the watershed’s runoff. It also appears that the water surface level of some lakes drops below the outlet elevation and when a rainfall occurs there isn’t any outflow monitored. Currently the model is over-predicting the watershed’s discharge during September and October. It is possible that enhancing the model to represent groundwater interactions could improve the calibration, but it is unlikely the only improvement required due to the seasonal variances described above. The cumulative volumetric discharge comparisons are a good match for 4 of the 5 monitoring locations.

2004 Volumetric

Discharge

Monitored (acre-ft)

Modeled (acre-ft)

Percent Difference

SM1 1,320 1,435 9%SM4 3,194 3,056 -4%SM6 4,033 3,087 -23%SM7 6,512 6,399 -2%SM8 10,100 10,367 3%

XP-SWMM under-predicts the volume at Forest Lake outlet (SM6) by 1,000 acre-ft. The calibration approach for SM6 was to maximize the amount of runoff from contributing subwatersheds, but the model still fell short of monitored values. This could be due to groundwater interactions of landlocked subwatersheds. If a constant 10-cfs were added to the model predictions until late June (add 1,500 acre-ft volume), the visual comparison of discharges would improve (until June 15,) as would the volumetric comparisons. While the XP-SWMM model is lower than monitored at SM6, the Water Budget matches the volumes because it is tied to the monitoring data. The Water Budget also assigns a volume number to the localized groundwater interactions of landlocked subwatersheds. After the model was calibrated for the 2004 monitoring period, the XP-SWMM model simulated the modified water year precipitation records for average (2004), wet (2003), and dry (2005) conditions.

Page 6 of 6 Model Enhancements In future modeling efforts the following could be completed to enhance the model’s predictive abilities.

• Refine Birch Lake’s depth to storage curve in HYDRAULICS, using WCD 2006 bathymetry survey. Explicitly model precipitation and evaporation on the lake surface in RUNOFF as an open water feature.

• Refine School Lake’s depth to storage curve in HYDRAULICS, using WCD 2006 bathymetry survey. Explicitly model precipitation and evaporation on the lake surface in RUNOFF as an open water feature.

• Survey field road crossing downstream of School Lake and explicitly model in HYDRAULICS.

• Survey Shield Lake Outlet and explicitly model in HYDRAULICS • Survey a couple cross-sections in the wetland downstream of Comfort Lake outlet; refine the

HYDRAULICS to explicitly model the wetland. • Formally survey the rock weir downstream of Comfort Lake outlet to confirm model

elevations. Collect more stream gauging events for refinement of rating curve used for monitoring.

• Monitor and analyze water surface levels in Forest Lake three basins, evaluate if basins should be modeled hydraulically as three separate storage nodes.

• Develop and implement approach for modeling groundwater interactions from landlocked subwatersheds. Conduct groundwater monitoring for principal lakes and several stations between Forest Lake outlet and Comfort Lake inlet. Revisit average (2004) conditions calibration.

• Consider development of two runoff models, by changing ONLY the infiltration parameters. One model representing frozen ground conditions and another for typical summer conditions.

• Monitor and model City of Forest Lake storm water collection system.

Stream Monitor (SM1)

T:\1676-CLFLWD\01\16 - Reports\REPORT - FINAL-101907\Appendix B\Stream Monitor-SM1-8 10/18/2007 1:48 PM

CLFLWD Volumetric Comparison - Model vs Monitor - SM1 Bone Lake Outlet

-

200

400

600

800

1,000

1,200

1,400

1,600

3/23/20040:00

4/7/20040:00

4/22/20040:00

5/7/20040:00

5/22/20040:00

6/6/20040:00

6/21/20040:00

7/6/20040:00

7/21/20040:00

8/5/20040:00

8/20/20040:00

9/4/20040:00

9/19/20040:00

10/4/20040:00

10/19/2004 0:00

11/3/20040:00

Date Time

Cum

mla

tive

Vol

ume

(acr

e-ft

)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

Rainfall (in)

SM#1 (rainfall) XP-SWMM SM#1 L115 Area-Velocity Probe Discharge (cfs) Percent Total Average Rainfall (%) [20.8-inches]



CLFLWD Volumetric Comparison - Model vs Monitor - SM4 Little Comfort Lake Inlet

-

500

1,000

1,500

2,000

2,500

3,000

3,500

3/23/20040:00

4/7/20040:00

4/22/20040:00

5/7/20040:00

5/22/20040:00

6/6/20040:00

6/21/20040:00

7/6/20040:00

7/21/20040:00

8/5/20040:00

8/20/20040:00

9/4/20040:00

9/19/20040:00

10/4/20040:00

10/19/2004 0:00

11/3/20040:00

Date Time

Cum

mla

tive

Vol

ume

(acr

e-ft

)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

Rainfall (in)

SM#4 (rainfall) XP-SWMM SM#4 LLCL-9 Area-Velocity Probe Discharge (cfs) tailwater Percent Total Average Rainfall (%) [20.8-inches]

Tailwater 7/3/04 to year end



CLFLWD Volumetric Comparison - Model vs Monitor - SM6 Forest Lake Outlet

-

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

4,500

3/23/20040:00

4/7/20040:00

4/22/20040:00

5/7/20040:00

5/22/20040:00

6/6/20040:00

6/21/20040:00

7/6/20040:00

7/21/20040:00

8/5/20040:00

8/20/20040:00

9/4/20040:00

9/19/20040:00

10/4/20040:00

10/19/2004 0:00

11/3/20040:00

Date Time

Cum

mla

tive

Vol

ume

(acr

e-ft

)

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

Rainfall (in)

XP-SWMM SM#6 L272 SM#6: Rating Curve Discharge (cfs) Percent Total Average Rainfall (%) [20.8-inches]



CLFLWD Volumetric Comparison - Model vs Monitor - SM7 Comfort Lake Inlet (from Shallow Pond)

1

1,001

2,001

3,001

4,001

5,001

6,001

7,001

3/23/20040:00

4/7/20040:00

4/22/20040:00

5/7/20040:00

5/22/20040:00

6/6/20040:00

6/21/20040:00

7/6/20040:00

7/21/20040:00

8/5/20040:00

8/20/20040:00

9/4/20040:00

9/19/20040:00

10/4/20040:00

10/19/2004 0:00

11/3/20040:00

Date Time

Cum

mla

tive

Vol

ume

(acr

e-ft

)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

Rainfall (in)

SM#7 (rainfall) XP-SWMM SM#7 CL39 out Area-Velocity Probe Discharge (cfs)SM#7: Rating Curve Discharge (cfs) Percent Total Average Rainfall (%) [20.8-inches]



CLFLWD Volumetric Comparison - Model vs Monitor - SM8 Comfort Lake Outlet

-

2,000

4,000

6,000

8,000

10,000

12,000

3/23/20040:00

4/7/20040:00

4/22/20040:00

5/7/20040:00

5/22/20040:00

6/6/20040:00

6/21/20040:00

7/6/20040:00

7/21/20040:00

8/5/20040:00

8/20/20040:00

9/4/20040:00

9/19/20040:00

10/4/20040:00

10/19/2004 0:00

11/3/20040:00

Date Time

Cum

mla

tive

Vol

ume

(acr

e-ft

)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

Rainfall (in)

SM#8 (rainfall) XP-SWMM SM#8 CL54A out Area-Velocity Probe Discharge (cfs)SM#8: Rating Curve Discharge (cfs) MN DNR Modified Rock Weir Percent Total Average Rainfall (%) [20.8-inches]

MN DNR modified Rock Weir 7/21/04


T:\1676-CLFLWD\01\16 - Reports\DRAFT_REPORT_CD\Appendix_C_XPS\Appendix_Calib_04_Q_036 10/18/2007 1:54 PM

CLFLWD Discharge Comparison - Model vs Monitor - SM1 Bone Lake Outlet

0.0

5.0

10.0

15.0

20.0

25.0

3/23/20040:00

4/7/20040:00

4/22/20040:00

5/7/20040:00

5/22/20040:00

6/6/20040:00

6/21/20040:00

7/6/20040:00

7/21/20040:00

8/5/20040:00

8/20/20040:00

9/4/20040:00

9/19/20040:00

10/4/20040:00

10/19/2004 0:00

11/3/20040:00

Date Time

Dis

char

ge (c

fs)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

Rainfall (in)

SM#1 (rainfall) XP-SWMM SM#1 :L115 Area-Velocity Probe Discharge (cfs)SM#1: Rating Curve Discharge (cfs) SM#1 Baseflows: Q during 5-day periods of no precip Total Gauged Discharge (cfs)

.



CLFLWD Discharge Comparison - Model vs Monitor - SM4 Little Comfort Lake Inlet

-10.0

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

3/23/20040:00

4/7/20040:00

4/22/20040:00

5/7/20040:00

5/22/20040:00

6/6/20040:00

6/21/20040:00

7/6/20040:00

7/21/20040:00

8/5/20040:00

8/20/20040:00

9/4/20040:00

9/19/20040:00

10/4/20040:00

10/19/2004 0:00

11/3/20040:00

Date Time

Dis

char

ge (c

fs)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

Rainfall (in)

SM#4 (rainfall) XP-SWMM SM#4 :LLCL-9 Area-Velocity Probe Discharge (cfs)SM#4: Rating Curve Discharge (cfs) SM#4 Baseflows: Q during 5-day periods of no precip Total Gauged Discharge (cfs)

Tailwater 7/3/04 to year end



CLFLWD Discharge Comparison - Model vs Monitor - SM6 Forest Lake Outlet

0.0

10.0

20.0

30.0

40.0

50.0

60.0

3/23/20040:00

4/7/20040:00

4/22/20040:00

5/7/20040:00

5/22/20040:00

6/6/20040:00

6/21/20040:00

7/6/20040:00

7/21/20040:00

8/5/20040:00

8/20/20040:00

9/4/20040:00

9/19/20040:00

10/4/20040:00

10/19/20040:00

11/3/20040:00

Date Time

Dis

char

ge (c

fs)

add 10-cfs constant to model until June 15 XP-SWMM SM#6 :L272 SM#6: Rating Curve Discharge (cfs)SM#6 Baseflows: Q during 5-day periods of no precip Total Gauged Discharge (cfs)



CLFLWD Discharge Comparison - Model vs Monitor - SM7 Comfort Lake Inlet (from Shallow Pond)

0.7

10.7

20.7

30.7

40.7

50.7

60.7

70.7

80.7

90.7

3/23/20040:00

4/7/20040:00

4/22/20040:00

5/7/20040:00

5/22/20040:00

6/6/20040:00

6/21/20040:00

7/6/20040:00

7/21/20040:00

8/5/20040:00

8/20/20040:00

9/4/20040:00

9/19/20040:00

10/4/20040:00

10/19/2004 0:00

11/3/20040:00

Date Time

Dis

char

ge (c

fs)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

Rainfall (in)

SM#7 (rainfall) XP-SWMM SM#7 :CL39 out Area-Velocity Probe Discharge (cfs)SM#7: Rating Curve Discharge (cfs) SM#7 Baseflows: Q during 5-day periods of no precip Total Gauged Discharge (cfs)



CLFLWD Discharge Comparison - Model vs Monitor - SM8 Comfort Lake Outlet

0.0

20.0

40.0

60.0

80.0

100.0

120.0

3/23/20040:00

4/7/20040:00

4/22/20040:00

5/7/20040:00

5/22/20040:00

6/6/20040:00

6/21/20040:00

7/6/20040:00

7/21/20040:00

8/5/20040:00

8/20/20040:00

9/4/20040:00

9/19/20040:00

10/4/20040:00

10/19/2004 0:00

11/3/20040:00

Date Time

Dis

char

ge (c

fs)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

Rainfall (in)

SM#8 (rainfall) XP-SWMM SM#8 :CL54A out Area-Velocity Probe Discharge (cfs) SM#8SM#8: Rating Curve Discharge (cfs) SM#8 Baseflows: Q during 5-day periods of no precip MN DNR Modified Rock WeirTotal Gauged Discharge (cfs) Percent Total Average Rainfall (%) [20.8-inches]

MN DNR modified Rock Weir 7/21/04

Shield Lake - Lake Level Comparison

900.8

901

901.2

901.4

901.6

901.8

902

902.2

902.4

902.6

3/4/2004 4/23/2004 6/12/2004 8/1/2004 9/20/2004 11/9/2004 12/29/2004

Date Time

Lak

e L

evel

(ele

vatio

n ft

)

Shield Lake; MN DNR Lake Finder - Lake Level [ele] Forest Lake; MN DNR Lake Finder - Lake Level [ele]XP-SWMM - Shields Lake (FL62)

Bone Lake - Lake Level Comparison

907.6

907.8

908

908.2

908.4

908.6

908.8

909

909.2

909.4

909.6

909.8

3/4/2004 4/23/2004 6/12/2004 8/1/2004 9/20/2004 11/9/2004 12/29/2004

Date Time

Lak

e L

evel

(ele

vatio

n ft

)

Bone Lake; MN DNR Lake Finder - Lake Level [ele] XP-SWMM - Bone Lake (SBL01)

Forest Lake - Lake Level Comparison

900.8

901

901.2

901.4

901.6

901.8

902

902.2

3/4/2004 4/23/2004 6/12/2004 8/1/2004 9/20/2004 11/9/2004 12/29/2004

Date Time

Lak

e L

evel

(ele

vatio

n ft

)

Forest Lake; MN DNR Lake Finder - Lake Level [ele] XP-SWMM - Forest Lake (FL01)

Little Comfort Lake - Lake Level Comparison

885

885.5

886

886.5

887

887.5

888

888.5

3/4/2004 4/23/2004 6/12/2004 8/1/2004 9/20/2004 11/9/2004 12/29/2004

Date Time

Lak

e L

evel

(ele

vatio

n ft

)

Little Comfort Lake; MN DNR Lake Finder - Lake Level [ele] XP-SWMM - Little Comfort Lake (LCL02)

Comfort Lake - Lake Level Comparison

885

885.5

886

886.5

887

887.5

888

3/4/2004 4/23/2004 6/12/2004 8/1/2004 9/20/2004 11/9/2004 12/29/2004

Date Time

Lak

e L

evel

(ele

vatio

n ft

)

Comfort Lake; MN DNR Lake Finder - Lake Level [ele] XP-SWMM - Comfort Lake (CL54)

Monitoring Station Rating Curves

Documents

Appendix B Watershed Hydrology/Hydraulics