Wetland Health Evaluation Plan (WHEP)

 

In 2006 Hennepin County invited the Commission to participate in a new program called WHEP – the Wetland Health Evaluation Program.

 

WHEP utilizes volunteers to collect macroinvertebrate and plant data on wetlands.  That data is used to calculate an Index of Biotic Integrity (IBI) for each monitored wetland.  The IBI can be used as an indicator of general wetland health and as a metric to help detect change.  Changes in hydrology, water quality, etc. will be reflected in the types of plant communities in the wetland and by the pollution-tolerance of the macroinvertebrates.

 

In 2006 the Commissions participated in WHEP with two wetlands – one in Plymouth near Timber Shores Park where Bass Creek outlets from Bass Lake (in the Shingle Creek watershed) and the second in the Brooklyn Park Environmental Preserve (West Mississippi).

 

The Bass Lake wetland is a large 33-acre wetland with a large 1,000-acre watershed that has approximately 20% impervious surface.  This Type 3 wetland is expected to be a high quality reference site.  It is part of the City of Plymouth’s stormwater management plan and is designated as Exceptional Quality.  Bass Lake is immediately upstream of this wetland.

 

The invertebrate evaluation resulted in a Moderate rating and in IBI score of 16, an improvement over last year’s rating of Moderate to Poor.  The vegetation evaluation remained constant with a Poor+ rating.  The vegetation and invertebrate scores are consistent from year to year and good baseline data has been established.

 

The wetland in the West Mississippi watershed is located in the Brooklyn Park Environmental Preserve.  It is a 0.75-acre Type 5 wetland located in a 590-acre watershed within the City’s Environmental Area.  It has approximately 30% impervious cover and is surrounded on three sides by wetlands, with a narrow unmowed strip on the fourth side.  The goal for this wetland is to detect changes in the biotic community, better understand stresses and preserve the functions of the wetland.  The rating for invertebrates in this wetland was Excellent, the best in Hennepin County, with a total IBI score of 28.  The wetland vegetation was rated Poor.  Reed canary grass was estimated to have over 50% coverage and was the dominant species found.

 

The 2006 Hennepin Field Season Summary of Minnesota Wetland Health Evaluation Program is available by contacting mary.karius@co.hennepin.mn.us.

 

 

Wetland Management Plan

 

Minnesota Rules Section 8410.0060 requires watershed management plans to include an inventory of the functional values of wetlands in the watershed, or to set forth a plan to create that inventory within a given time frame. The Commissions’ Second Generation Management Plan requires member cities to prepare the assessments according to a plan and schedule found in the Water Quality Plan (WQP).  In addition, the WQP identifies the need to establish a management strategy and priority system for wetlands based on their watershed significance to accomplish the protection, preservation, and possible restoration of high quality wetlands.

 

To meet state requirements and to develop a Wetland Management Plan (WMP), an assessment of the existing wetlands functions and values is needed to prioritize the wetlands in a manner that allows effective management decisions.  The WMP will use existing wetland data sources and the results of the wetland functions and values inventory to develop a long term management plan for wetlands in the two watersheds.

 

The Board of Water and Soil Resources (BWSR) has developed criteria and a methodology for determining the functions and values of a wetland, the Minnesota Routine Assessment Methodology (MnRAM).  The Commissions propose to use the most recent version of MnRAM in the WMP.  Some MnRAM assessments using an older version have already been completed and will be incorporated into the WMP as-is or possibly with additional data collection.

 

Phase I of the WMP is the assessment of wetland functions and values of Priority Wetlands to identify wetlands that currently have high intrinsic value to the community, provide needed flood storage and water quality treatment, have diverse vegetation, and provide wildlife habitat.  This information will be used in Phase II of the WMP to develop wetland management strategies, identify water quality improvement projects and wetland restoration opportunities, improve public recreation and education opportunities, and evaluate rules and standards for future development and re-development impacting wetlands.   These assessments must be completed by May 2009.

 

The Wetland Management Plan was identified in previous planning documents such as the Second Generation Plan as a Wetland Protection and Preservation Plan.  The WMP will have utility not only to the Commissions but also to the member cities.  This task will develop the outline of the WMP through coordination with the TAC.  It is important to complete this outline early in the process to be sure that the field data being collected by the cities includes all the data elements necessary to complete the analysis of wetland conditions and development of management strategies.

 

Phase II of the Wetland Management Plan will be completed in 2009.  Using the data gathered in Phase I and the outline developed in Task 3 above, the Wetland Management Plan will summarize findings on the condition of wetlands in the watersheds; set forth management strategies to protect and preserve the remaining high-quality wetlands and improve and protect the other wetlands in the watersheds; and identify programs and projects for consideration for inclusion in the Capital Improvement Program and the Third Generation Management Plan. 

 

 

What are Wetland Functions and Values?

 

Extracted from:  “Restoration, Creation, and Recovery of Wetlands: Wetland Functions, Values, and Assessment” by Richard P. Novitzki, ManTech Environmental Technology, Inc. , R. Daniel Smith, U.S. Army Corps of Engineers, Judy D. Fretwell, U.S. Geological Survey

 

Wetland functions are defined as a process or series of processes that take place within a wetland.  These include the storage of water, transformation of nutrients, growth of living matter, and diversity of wetland plants, and they have value for the wetland itself, for surrounding ecosystems, and for people.  Functions can be grouped broadly as habitat, hydrologic, or water quality, although these distinctions are somewhat arbitrary and simplistic.  For example, the value of a wetland for recreation (hunting, fishing, bird watching) is a product of all the processes that work together to create and maintain the wetland.   Not all wetlands perform all functions nor do they perform all functions equally well. The location and size of a wetland may determine what functions it will perform.  For example, the geographic location may determine its habitat functions, and the location of a wetland within a watershed may determine its hydrologic or water-quality functions.

 

Perhaps wetlands are best known for their habitat functions, which are the functions that benefit wildlife. They provide food, water, and shelter for fish, shellfish, birds, and mammals, and they serve as a breeding ground and nursery for numerous species. 

 

Hydrologic functions are those related to the quantity of water that enters, is stored in, or leaves a wetland.  These functions include such factors as the reduction of flow velocity, the role of wetlands as ground-water recharge or discharge areas, and the influence of wetlands on atmospheric processes.  Water-quality functions include the trapping of sediment, pollution control, and the biochemical processes that take place as water enters, is stored in, or leaves a wetland.

 

The value of a wetland lies in the benefits that it provides to the environment or to people, something that is not easily measured. Wetlands can have ecological, social, or economic values.  Wetland products that have an economic value, such as commercial fish or timber, can be assigned a monetary value.

 

 

What is MnRAM (Minnesota Routine Assessment Method)?

 

MnRAM is a structured tool for evaluating wetland function and value that was developed by the Board of Water and Soil Resources (BWSR) and a Technical Advisory Group and is periodically updated (most recent version is 3.1).  It is a series of questions that are scored on various scales, with the results compiled into an index that provides an overall assessment of wetland condition.  The evaluation is best performed by a trained, experienced field technician with plant identification skills and an understanding of surface and groundwater hydrology.

 

Wetland functions/value characteristics evaluated in MnRAM 3.1:

§    Maintenance of Characteristic           Vegetative Diversity/Integrity	§    Maintenance of Characteristic Wildlife     Habitat Structure
§    Maintenance of Hydrologic Regime	§    Maintenance of Characteristic Fish Habitat
§    Flood/Stormwater Attenuation	§    Maintenance of Characteristic Amphibian     Habitat
§    Downstream Water Quality	§    Aesthetics/Recreation/Education/Cultural
§    Maintenance of Wetland Water         Quality	§    Commercial Uses
§    Shoreline Protection	§    Ground Water Interaction

 

Additional evaluation information gathered in MnRAM 3.1:

§    Restoration Potential

§    Sensitivity to Stormwater & Urban Development

§    Additional Stormwater Treatment Needs