1993 NR-MI-6199-S

Water Quality and Fisheries

"Minnesota 's Forest Resources at a Crossroads" is a series of 15 briefs that summarizes the draft version of a Generic Environmental Impact Statement (GElS). The GElS identifies and assesses the environmental, economic, and social impacts of potential increases in timber harvesting and forest management activities in Minnesota. The GElS also develops mitigation strategies for these impacts and offers strategic policy recommendations. The study was commissioned by the Minnesota Environmental Quality Board. This information forms the basis for discussion about the future protection and management of Minnesota's forest resources.

How to obtain copies:

The draft GElS document is lengthy and is based on information contained in five background papers and nine technical papers. These briefs parallel the GElS document and the background and technical papers. Copies of the GElS documents can be obtained by contacting Dr. Michael A. Kilgore, Environmental Quality Board, 300 Centennial Office Building, 658 Cedar Street, St. Paul, MN 55155 (Phone: 612/297-2607). Additional copies of the briefs can be obtained by writing the Minnesota Extension Service Distribution Center, Room 20 Coffey Hall, 1420 Eckles Avenue, st. Paul, MN 55108 OR fax in your order at 612 /625.2207. Request item number NR·MI-6199-S, entitled "Minnesota's Forest Resources at a Crossroads."

This brief summarizes the extent to which Minnesota's water resource is impacted by timber harvesting and other forest management activities. The original analysis in the GElS Water Quality and Fisheries technical paper was developed from literature reviews and professional experience. It was prepared by a seven-member study group representing water quality, hydrology, fisheries, and ecological disciplines. Water quality and fisheries were handled together by the study group because of the natural linkage between the two.

Background

Minnesota enjoys an abundance of high quality water. The state has over 25,000 miles of fishable streams, over 15,000 lakes, 7 million acres of wetlands, and substantial groundwater supplies. The worth of these resources is important in terms of economic benefits as well as for wildlife habitat and quality of life values.

Timber harvesting and forest management activities are extensive by nature . The combination of these extensive forestry operations and the abundance of water resources means that there will be many interactions between the two. However, individual stands of trees are affected only periodically and usually for short periods of time, such as during harvesting, road building, and stand establishment These time periods are generally followed by long interludes with no disturbance

from forestry activities. In contrast, agricultural land uses, which accowlt for about half of Minnesota's land area, represent a more serious threat to water qUality. Much of the state's

) cropland is disturbed and susceptible to erosion each year, and large quantities of fertilizer and pesticides are routinely applied.

The gentle topography and generally stable soils over much of the state reduce the risk of soil erosion that impacts water quality and aquatic ecosystems. However, poor timing and/or use of inappropriate techniques and harvesting systems can cause significant localized erosion adversely affecting both water quality and aquatic ecosystems. If these poor practices are repeated elsewhere in the same catchment (body of water), the potential exists for cumulative impacts to occur.

Impacts on water resources are not confmed to the site where disturbance has occurred. Therefore, it is important to develop and implement standards of practice that can reduce impacts irrespective of ownership. Minnesota forest management agencies and industries have developed and addressed a series of voluntary forest water quality Best Management Practices (BMPs). Using BMPs will reduce the likelihood of impacts resulting from forest management and timber harvesting. In addition to these practices, effective and timely regeneration of the new forest cover represents a major

way in which soil stability can be assured and therefore water quality values maintained.

Forest management also provides opportunities for improving water quality. Establishment of forest stands on abandoned farmland provides long-term stable cover of the soil resource. Establishment of forest cover in riparian (the banks of a stream, lake, or other body of water) areas can reduce erosion and the transport of chemicals from nearby agricultural lands. Integration of forest management with conventional farming activities can also mitigate the problems of providing shelter from wind erosion and can help foster retention of soil moisture.

Best Management Practices (BMPs)

Minnesota's BMPs are a set of guidelines that have been developed to reduce the impact of timber harvesting and forest management activities on water quality and aquatic ecosystems. These BMPs present specific recommended practices for harvest planning, road construction, harvest activity, site preparation, prescribed burning, and pesticide applications. Most of these recommended practices address issues dealing with erosion and movement of detritus (disintegrated material or debris), nutrients, and toxic chemicals into a body of water.

BMPs are presented and managed as a voluntary program in Minnesota, although there appears to be a legal route for their enforcement through the state's Shoreline Management Regulations. Based on interviews with consulting foresters and on the study group members'

professional experience, asswnptions of compliance with BMPs linked to ownership have been made. These are set out in Table I. Recent evidence from field audits suggests that these estimates are reasonable.

Table 1 • Assumed and estimated BMPs compliance In Minnesota.

State 90 80 (t7)

County 90 90 (10)

Federal 90 87 (1 t)

Forest Industry 90 88 (12)

71 (21)Nonindustrial 50 Private

• Percentage refers to sites rated as having adequate application. The figures in brackets are the percentages rated as having a minor departure from BMPs .

Present Condition and Anticipated Impacts

Water bodies in Minnesota's forested regions are generally of high quality and are not currently subject to significant broad-scale human impact. However, these water resources can be impacted locally for temporary periods of time.

Sedimentation. The risk of high rates of sediment production due to current or proposed levels of timber harvesting is Jow for Minnesota. The state's relatively flat landscape reduces the ability of water to transport sediment from the land surface to water. Roads in most areas of the state do not contribute much sediment input for precisely the same reason (i.e., surface flow is restricted by low slopes). There are areas of the state with highly sloping, variable terrain that exhibit naturally high rates of erosion and sediment production with or without harvest

activity (e.g., the North Shore or the bluffland region of southeast Minnesota).

Implementation of BMPs in areas of high slopes and erodible soils will reduce the level of sediment-related impacts, as will restricting harvest activities to less sensitive times of the year such as winter when the ground is frozen. Most timber harvesting activities in Minnesota follow procedures outlined in the state's BMPs (there is from 70 to nearl y 100 percent compliance across all land ownerships).

Changes in land use away from forested conditions can lead to changes in sediment production. Timber harvesting activities examined in the GElS process are carried out using standard silvicultural techniques where trees replace trees. The land is not converted to other uses. Thus, managed forest will replace managed forest. Sediment relationships will not significantly deviate from the level of natural variation as long as sites remain forested and BMPs are adequately applied at all timber harvest sites.

Nutrient loading. Increased timber harvesting by itself is not likely to pose a significant threat to the nitrogen balance of lakes or streams in Minnesota. Predicted increases in phosphorus concentrations in streams and lakes will not reach levels likely to cause eutrophication (overfertilization of a body of water by nutrients resulting in the production of more organic matter than a natural-purification process can overcome).

Runoff, fertilizers, compost, sludges, and pesticides. No adverse effects to water quantity or the pattern of streamflow that

cause undue runoff in any region of the state are predicted to occur under any timber harvesting scenario. There is minimal, if any, fertilization of forest lands in Minnesota. As this is unlikely to change, there are no demonstrable effects of forest fertilization at present and none is predicted. Compost is not currently used on Minnesota forested lands and municipal sludge has been used on only one site. Water quality impacts from this one sludge application are not evident. Pesticide use is minimal on forested lands and if this pattern continues, no regional impact on water resources is anticipated.

Light and temperature. If stream corridors are harvested to the water's edge, large increases in light reaching the stream channel will occur. This can increase the temperature of smaller streams and change the species composition and rates of production in the stream community. These impacts are local, so are not evident at the regional level. If watershed areas are harvested in compliance with BMPs, no significant effects on light or temperature are expected.

Organic matter. Harvesting in compliance with BMPs may change species composition in the riparian zone, thereby altering the quantity and chemistry of leaf material that enters a stream or lake. Such changes would probably alter the species composition of insects in the stream of the riparian zone of the lake, which in tum may affect the fish community. In general, however, such changes are expected to be minimal.

Course woody debris. Wood provides a substrate, food resource, and habitat for stream and lake organisms. Wood also

serves to control the stream channel (i.e., through debris dams, overhangs, channel obstructions). Changes in the riparian zone due to timber harvesting can change inputs of wood to streams, lakes, and wetlands. These changes would be most important to small streams, thereby exerting influence on a local, site-specific basis. Effects might include changes in stream animal popUlations, in rates of flow, and in energy utilization patterns. Again, if BMPs are adequately applied, changes in riparian zones due to timber harvesting and thus changes to inputs of wood to bodies of water, will be minimal if they occur at all.

Forest dependent fish and other organisms. There are about 150 species of fish in Minnesota. Most of these species can be found, at least in some life stages, in forested areas. If BMPs are complied with at all timber harvesting sites, no great impacts to fish communities are predicted. Harvesting in compliance with BMPs will also have no adverse impacts on stream and lake plants like algae and macroinvertebrates like snails.

Conclusion

Analysis of the effects of timber harvesting indicate that there will be no changes in the water resource that will exceed the thresholds specified by the state's Environmental Quality Board. However, there will be a series of changes in the landscape and in the water resource. Most of these changes will be relatively local and short-lived. Timber harvesting done in compliance with Minnesota BMPs will have significantly fewer local water resource impacts than will timber harvesting done in the absence of BMPs.

Timber harvesting is, by its vel)' nature, a disturbance to the community and the landscape. The degree to which a given disturbance represents an impact is a matter of scale. That is , few if any landscape modifications associated with timber harvesting will be detectable in large rivers such as the upper Mississippi. As one progresses further upstream, one is more likely to detect changes outside of the identified standards and tolerances and therefore the probability of detecting impacts increases.

Smaller watersheds harvested without adherence to BMPs will exhibit a variety of local scale changes. Probably the most dramatic of these small-scale changes will be increases in sediment production in streams in some areas, increases in light and decreases in large woody debris in streams and lakes, and decreases in stream fish population densities in some regions. Some small watershed areas harvested using BMPs are still expected to have measurable increases in nutrient loads, sectiment loads, and stream channel morphology and will have altered (not necessarily worse) structure and functional rates of aquatic communities. These changes will generally be limited to a few hundred meters below a timber harvest site.

Changes in water quality under the harvesting scenarios presented in the GElS study are not evident at either region or statewide levels . As a consequence, no significant impacts have been identified in the analysis presented in the GElS Water Quality and Fisheries Technical Paper. However, changes could occur at a local site-specific level. Therefore, the technical paper identifies measures

that can reduce impacts at this scale.

Alternative Management Options

A variety of broad-scale interagency coordination and monitoring of regional harvesting activities coupled with site-specific mitigative strategies are suggested. The most important of these is implementation of forest water quality BMPs. BMPs are well-respected and widely (but not uniformly) used in Minnesota. They appear to be highly effective in avoiding or minimizing impacts to the water resource. Several modifications to the BMPs manual and its implementation are suggested in the GElS Water Quality and Fisheries Technical Paper. Foremost among these modjfications are monitoring and enforcement of existing water quality rules, regulations, and laws . The technical paper goes on to suggest that better monitoring to detect impacts, better monitoring of BMPs implementation, and better education about the need for and use of BMPs will all play an important part in protecting Minnesota waters from adverse timber harvest impacts.

Sponsors:

Minnesota Environmental Quality Board

Minnesota Forestry Coordinating Committee

Minnesota Society of American Foresters

Minnesota Extension Service, University of Minnesota

The University of Minnesota. is an equal opportunity educator..and employer.

ft Printed on recycled paper with ";I 10% post-consumer waste.