Forestville Flowage, Ahnapee River Watershed (TK04)
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Forestville Flowage, Ahnapee River Watershed (TK04)
Forestville Flowage (95700)
94.02 Acres
Natural Community
Natural communities (stream and lake natural communities) represent model results that use predicted flow and temperature based on landscape features and related assumptions. Ranges of flow and temperature associated with specific aquatic life communities (fish, macroinvertebrates) help biologists identify appropriate resource management goals. Wisconsin Natural Communities.
Impounded Flowing Water
Year Last Monitored
This is the most recent date of monitoring data stored in SWIMS. Additional surveys for fish and habitat may be available subsequent to this date.
2024
Good
 
Door
Trout Water 
Trout Waters are represented by Class I, Class II or Class III waters. These classes have specific ecological characteristics and management actions associated with them. For more information regarding Trout Classifications, see the Fisheries Trout Class Webpages.
No
Outstanding or Exceptional 
Wisconsin has designated many of the state's highest quality waters as Outstanding Resource Waters (ORWs) or Exceptional Resource Waters (ERWs). Waters designated as ORW or ERW are surface waters which provide outstanding recreational opportunities, support valuable fisheries and wildlife habitat, have good water quality, and are not significantly impacted by human activities. ORW and ERW status identifies waters that the State of Wisconsin has determined warrant additional protection from the effects of pollution. These designations are intended to meet federal Clean Water Act obligations requiring Wisconsin to adopt an 'antidegradation' policy that is designed to prevent any lowering of water quality - especially in those waters having significant ecological or cultural value.
No
Impaired Water 
A water is polluted or 'impaired' if it does not support full use by humans, wildlife, fish and other aquatic life and it is shown that one or more of the pollutant criteria are not met.
No

Fish and Aquatic Life

Current Use
The use the water currently supports. This is not a designation or classification; it is based on the current condition of the water. Information in this column is not designed for, and should not be used for, regulatory purposes.
Impounded Flowing Water
This classification includes waterbodies created by dams (mill ponds, reservoirs, flowages, and other impoundments) with a residence time of 14 days or more (under summer (June – Sept) mean low flow conditions with a 1 in 10 year recurrence interval (US EPA 2000)). Many natural lakes also have dams or water level control structures. However, to be included in the Impounded Flowing Waters category, the dam or water level control structure, must account for more than half of a waterbody’s maximum depth. Impoundments with a residence time of less than 14 days should be covered under the rivers and stream assessment methodology process.
Attainable Use
The use that the investigator believes the water could achieve through managing "controllable" sources. Beaver dams, hydroelectric dams, low gradient streams, and naturally occurring low flows are generally not considered controllable. The attainable use may be the same as the current use or it may be higher.
Default FAL
Fish and Aquatic Life - Default Waters do not have a specific use designation subcategory but are considered fishable, swimmable waters.
Designated Use
This is the water classification legally recognized by NR102 and NR104, Wis. Adm. Code. The classification determines water quality criteria and effluent limits. Waters obtain designated uses through classification procedures.
Default FAL
Fish and Aquatic Life - Default Waters do not have a specific use designation subcategory but are considered fishable, swimmable waters.

Overview

Forestville Flowage is a 65-acre impoundment on the Ahnapee River at Forestville. It has a maximum depth of 5 feet. The village of Forestville owns and operates the dam that forms this impoundment. The upper Ahnapee River and the Forestville Flowage were chemically treated in 1984 to remove carp and bullheads.

They were later restocked with bass, panfish and northern pike (Meyers, 1995). Smallmouth bass are present and northern pike, largemouth bass and panfish are common. A fish kill occurred in January 1990. Intermittency and stagnation are probably responsible for depleted dissolved oxygen levels and winterkill in this lake. Waterfowl rest on the lake and nest in adjacent wooded swamps.

The Negative impacts of the Forestville Dam and it�s impoundment on the natural stream ecosystem functional values for the Ahnapee River should be considered the next time significant repairs or replacement are needed on the dam. The impoundment behind the dam has periodic fish kills and intermittent water
quality problems that would be alleviated if the Dam were removed.

Krohns Lake has a surface area of 21 acres and a maximum depth of 38 feet. It is a spring-fed lake with fair to good water quality and good dissolved oxygen concentrations. The lake does receive some nutrient enrichment from watershed runoff although the shoreline is generally well-buffered. The fishery includes
largemouth bass, northern pike, panfish, and rainbow and brown trout. Rainbow trout are stocked by WDNR. A county park provides a swimming beach, dock, boat launch (no motors) and parking.

Date  2002

Author   Aquatic Biologist

Historical Description

Source: 1965, Surface Water Resources of Door County Forestville Flowage, T26N, R25E, Section 29 Surface acres = 72.1, S.D.F. = 2.06, Maximum depth = 7 feet.

An impoundment of the Ahnapee River at Forestville, created in 1885 to provide mill power. At present a head of eight feet is maintained and the dam is owned by the Village of Forestville. The dam went out in 1960 and was replaced by a modern structure. Largemouth bass, northern pike, and panfish constitute the fishery. Weeds and fluctuating water levels are major use problems. A town park with about 200 feet of frontage provides access for swimming, picnicking, and boating. The upstream end is bordered by 173 acres of wooded swamp. Waterfowl nest and rest here and hunting is an important use.

Date  1965

Author   Surface Water Inventory Of Wisconsin

Forestville Flowage, Ahnapee River Watershed (TK04) Fish and Aquatic LifeForestville Flowage, Ahnapee River Watershed (TK04) RecreationForestville Flowage, Ahnapee River Watershed (TK04) Fish Consumption

Condition

Wisconsin has over 84,000 miles of streams, 15,000 lakes and milllions of acres of wetlands. Assessing the condition of this vast amount of water is challenging. The state's water monitoring program uses a media-based, cross-program approach to analyze water condition. An updated monitoring strategy (2015-2020) is now available. Compliance with Clean Water Act fishable, swimmable standards are located in the Executive Summary of Water Condition in 2018. See also the 'monitoring and projects' tab.

Reports

2020 Comprehensive WQ Assessments
Final Report for Comprehensive Lake Mangement Planning Grant Project #LPL162317 - Forestville Millpond
2018 List of Healthy (Category 2) Waters
Final Assessment Data from TSI Package and Assessment Units 2018
Forestville Flowage, Door County - Aquatic Plant Sampling Map (1) (33 mpts)
Forestville Flowage, Door County - Aquatic Plant Sampling Map (2) (33 mpts)
Forestville Flowage, Door County - Aquatic Plant Sampling Map (33 mpts)
Forestville Flowage, Door County - Garmin Text File
FORESTVILLE MILLPOND MANAGEMENT PLANNING
Final Report - Wisconsin Lake Management Planning Grant for the Forestville Millpond
Interim Project Status Wisconsin Lake Management Planning Grant for the Forestville Millpond
Interim Project Status Wisconsin Lake Management Planning Grant for the Forestville Millpond (flowage)
Forestville Millpond Water Chemistry and Secchi Readings (1994-1995)
Forestville Millpond Inorganic Chemistry (1990 & 1994)
Lake Bathymetry Map for Forestville Flowage

Recommendations

TMDL Development
Volunteer monitoring of TP and TSS on the Ahnapee River.
County Land and Water Management Plan
Door County Soil & Water Conservation Department proposes to conduct a phased approach to the development of protection strategies for its waters including lakes. This phase of the project will collect and analyze information regarding surface water resources in order to develop specific implementation recommendations for phase II indlucing upgrading regulatory programs. Project deliverables shall include a draft and final report containing: 1) an inventory and classification of county inland lakes; 2) appropriate supporting data and maps and; 3) recommendations specifying phase II implementation activities including proposed regulatory standards for shoreland and lake protection.

Management Goals

Wisconsin's Water Quality Standards provide qualitative and quantitative goals for waters that are protective of Fishable, Swimmable conditions [Learn more]. Waters that do not meet water quality standards are considered impaired and restoration actions are planned and carried out until the water is once again fishable and swimmable

Management goals can include creation or implementation of a Total Maximum Daily Load analysis, a Nine Key Element Plan, or other restoration work, education and outreach and more. If specific recommendations exist for this water, they will be displayed below online.

Monitoring

Monitoring the condition of a river, stream, or lake includes gathering physical, chemical, biological, and habitat data. Comprehensive studies often gather all these parameters in great detail, while lighter assessment events will involve sampling physical, chemical and biological data such as macroinvertebrates. Aquatic macroinvertebrates and fish communities integrate watershed or catchment condition, providing great insight into overall ecosystem health. Chemical and habitat parameters tell researchers more about human induced problems including contaminated runoff, point source dischargers, or habitat issues that foster or limit the potential of aquatic communities to thrive in a given area. Wisconsin's Water Monitoring Strategy was recenty updated.

Grants and Management Projects

Project Name (Click for Details)Year Started
DOOR COUNTY AIRPORT & PARKS DEPARTMENT: Forestville Millpond Management Planning1994
DOOR COUNTY: Forestville Mill Pond Comprehensive Lake Management Plan2017
DOOR COUNTY: LCO-Door County Inventory of Surface Water Resources1998
DOOR COUNTY LCD: Evaluation of the Forestville Millpond Following an Extended Drawdown2023
Ahnapee River TP and TSS2016
DOOR COUNTY: Door County AIS Coordination Project2005
Fish Propagation Actions2001

Monitoring Projects

WBICOfficial Waterbody NameStation IDStation NameEarliest Fieldwork DateLatest Fieldwork DateView StationView Data
95700Forestville Flowage10012295Forestville Flowage - Deep Hole6/16/19949/21/2024MapData
95700Forestville Flowage10053663Ahnapee River at Forestville Flowage5/28/20057/18/2023MapData
95700Forestville Flowage10001281Forestville Flowage6/1/19947/6/2019MapData
94800Ahnapee River10053663Ahnapee River at Forestville Flowage5/28/20057/18/2023MapData
95700Forestville Flowage153160Forestville Millpond - Above Dam7/5/19948/16/2023MapData
95700Forestville Flowage10037692Forestville Flowage nearshore9/6/20129/6/2012MapData
95700Forestville Flowage10019497Forestville Flowage -- Access at SE End Of Flowage6/9/20118/5/2015MapData

Watershed Characteristics

Forestville Flowage is located in the Ahnapee River watershed which is 135.58 mi². Land use in the watershed is primarily agricultural (49.80%), wetland (19.80%) and a mix of grassland (19.50%) and other uses (10.80%). This watershed has 189.28 stream miles, 5,768.81 lake acres and 15,037.67 wetland acres.

Nonpoint Source Characteristics

This watershed is ranked High for runoff impacts on streams, Not Ranked for runoff impacts on lakes and High for runoff impacts on groundwater and therefore has an overall rank of High. This value can be used in ranking the watershed or individual waterbodies for grant funding under state and county programs.However, all waters are affected by diffuse pollutant sources regardless of initial water quality. Applications for specific runoff projects under state or county grant programs may be pursued. For more information, go to surface water program grants.

Hydrological

This watershed is 50.00% impervious.

Natural Community

Forestville Flowage is considered a Impounded Flowing Water under the state's Natural Community Determinations.

Natural communities (stream and lake natural communities) represent model results and DNR staff valiation processes that confirm or update predicted conditions based on flow and temperature modeling from historic and current landscape features and related variables. Predicated flow and temperatures for waters are associated predicated fish assemblages (communities). Biologists evaluate the model results against current survey data to determine if the modeled results are corect and whether biological indicators show water quaity degradation. This analysis is a core component of the state's resource management framework. Wisconsin's Riverine Natural Communities.

This classification includes waterbodies created by dams (mill ponds, reservoirs, flowages, and other impoundments) with a residence time of 14 days or more (under summer (June – Sept) mean low flow conditions with a 1 in 10 year recurrence interval (US EPA 2000)). Many natural lakes also have dams or water level control structures. However, to be included in the Impounded Flowing Waters category, the dam or water level control structure, must account for more than half of a waterbody’s maximum depth. Impoundments with a residence time of less than 14 days should be covered under the rivers and stream assessment methodology process.

Fisheries & Habitat

The Forestville Millpond (WBIC-95700) is a 65 acre impoundment of the Ahnapee River located in southern Door County (WDNR 2001). The millpond has a maximum depth of 6 feet, an average depth of 2 feet and is located in an agricultural watershed. Historical records indicate that the first dam was constructed at this location in 1877 and the river has been impounded the majority of years since (Door County SWCD 1996). The current dam was reconstructed in 1982.

Historically the fishery found in the millpond has alternated between a desirable mix of Northern Pike, Largemouth Bass and panfish to one dominated by bullhead and Common Carp (Lychwick 1984). Poor water quality has likely been the driver of the make-up of fish community due to the shallow nature of the millpond and the level of nutrients that enter the millpond from the watershed. High nutrient levels have led to algae blooms which have then been followed by frequent winter kills caused by low dissolved oxygen as algae decomposed over winter.

Following the fish kills, the millpond has been restocked with a desirable mix of fish (Lychwick 1984) Following reconstruction of the dam in 1982, DNR Fish Management chemically treated the millpond using rotenone to remove undesirable fish species and restocked gamefish species (Lychwick 1984). Although the entire stream above the millpond was not treated, it was believed that the vast majority of Common Carp found in the impoundment were removed by the rotenone treatment. Following the rotenone treatment the millpond was restocked with a mixture of Largemouth Bass, Smallmouth Bass and Northern Pike.

Date  

Author  Steven Hogler