Delavan Lake Watershed Implementation Plan, 2016.pdf

The plan was developed by Berrini & Associates, LLC and Northwater Consulting under the sponsorship of the Town of Delavan. The primary goal is to improve and maintain water quality within the watershed by identifying causes of impairment, implementing best management practices (BMPs), and establishing clear cost estimates, priorities, and responsible parties.

Watershed Characterization:
- Geology & Soils: The watershed's geology comprises primarily glacial deposits with varying soil types, including sand, silt, and clay.
- Hydrologic Soil Groupings: These are categorized based on their water-holding capacity and erosion potential.
- Hydric Soils: Identified areas where water tables are typically at or above the surface year-round.
- Topography & Slope: The watershed features varied slopes, with a significant portion having moderate to steep inclines.
- Climate: Characterized by continental climate patterns with warm summers and cold winters.
- Landuse & Landcover: Predominantly agricultural with some residential areas, forests, and wetlands.

Watershed Hydrology and Environmental Corridors:
The Delavan Lake watershed drains into the lake through several streams and has a complex hydrologic system. Environmental corridors, such as rivers and wetlands, play a vital role in water quality protection.

Existing Wetlands and Impaired Areas:
- Existing Wetlands: The report identifies various types of wetlands within the watershed.
- Drained or Degraded Wetlands: Some areas have been impacted by drainage activities, leading to reduced water quality.
- Threatened/Endangered Species: The region supports several species at risk, emphasizing the need for habitat conservation.

Causes of Watershed Impairments:
- Pollutant Loading Sources: Suspended sediment and phosphorus are primary concerns, with critical loading areas identified.
- Highly Erodable Land (HEL): Agricultural practices on HEL contribute to sediment runoff.
- Septic Systems: Septic limiting soils and eroding gullies are issues requiring attention.

Nonpoint Source Management Measures:
The plan proposes a range of BMPs to reduce pollutant loading:
- Basin-Wide BMPs: Include comprehensive practices for soil conservation, buffer zones, and improved septic systems.
- Site-Specific BMPs: Tailored to individual land parcels, focusing on erosion control and nutrient management.
- Supplemental Measures: Involve public education, street sweeping, and stormwater management.

Costs, Priorities, and Responsible Parties:
- Cost Estimates: Provide a breakdown of probable costs for implementing the recommended BMPs.
- Priorities: Suggested priorities include soil conservation, septic system upgrades, and public education.
- Responsible Parties: Identify landowners, local governments, and relevant agencies as key stakeholders.

Technical and Financial Assistance:
The plan offers guidance on securing technical assistance from experts and financial support through grants and partnerships.

Information, Education, and Outreach:
A comprehensive outreach strategy is proposed to raise awareness about water quality issues and the importance of BMP implementation.

Implementation Schedule and Water Quality Targets:
Clear milestones and a timeline are outlined for successful implementation, with specific water quality targets set for Delavan Lake.

Monitoring Strategy:
A detailed monitoring plan ensures ongoing assessment of water quality improvements and the effectiveness of implemented BMPs.