In 2011, Illinois' Algonquin secured $1 million for a Woods Creek watershed plan. 10 years later, 27 projects costing $4.8 million had reduced pollution and improved the watershed for residents

Protecting water quality often requires long-term planning, cooperation, and projects that address pollution at its sources. The Woods Creek Watershed Plan in Illinois demonstrates how an initial investment can support broader restoration attempts involving communities, public agencies, private organizations, and residents.

Building a Watershed-Based Plan

In 2011, the Village of Algonquin received Clean Water Act (CWA) Section 319 funds to help develop a watershed-based plan for the Woods Creek watershed in McHenry County, Illinois. Over the following decade, communities and watershed partners worked together to put the plan into action.

At least 27 projects were completed in the 10-year period, with total costs surpassing $4.8 million. Municipalities, other public entities, and private and nonprofit partners carried out the projects.


The work included streambank stabilization and natural region restoration, which resulted in reductions in pollutant loads. When the original 10-year planning period ended, the Village of Algonquin submitted an updated plan to continue protecting and restoring the watershed.

Understanding the Woods Creek Watershed

The Woods Creek watershed extends in McHenry, Kane, and Cook counties in Illinois. It is a subwatershed of the Crystal Creek watershed, also known as Crystal Lake Outlet (HUC 071200061201).

The Crystal Creek watershed covers almost 20 square miles and borders the Woods Creek watershed to the north and east. Woods Creek flows into Lake-in-the-Hills Lake (IL-RTZZ) and Crystal Lake Outlet Creek (IL_DTZR-01), before continuing southeast toward Segment IL_DT-06 of the Fox River.

The watershed is primarily residential, with residential and commercial development representing the largest land uses. Runoff associated with nonpoint source pollution is the major risk to water quality.

Phosphorus, nitrogen, and sediment are common challenges in urbanized watersheds such as Woods Creek. Woods Creek has been listed as impaired for fecal coliform, while the Fox River has been listed as impaired for dissolved oxygen on the Clean Water Act Section 303(d) List of Impaired Waters since 2006.

Nutrient runoff from Woods Creek contributes to the dissolved oxygen impairment and to nutrient loadings that continue downstream through the Fox River and into the Mississippi River system.

A Comprehensive Plan for Water Quality

A detailed watershed-based plan for Woods Creek was developed in 2013. Its purpose was to address nonpoint source pollution and enhance conditions throughout the watershed.

The plan followed the U.S. Environmental Protection Agency’s watershed planning guidance from October 23, 2003, as revised. It also followed the Chicago Metropolitan Agency for Planning’s “Guidance for Developing Watershed Action Plans in Illinois” from June 2007, along with total maximum daily load (TMDL) implementation requirements and watershed planning principles.

The plan and its update concentrated on several water-quality and environmental objectives. These included refined stormwater management, flood reduction, enhanced natural area management, protection of groundwater recharge, green infrastructure, and invasive-species control.

Another objective was to improve ecosystem benefits within the Woods Creek watershed and ultimately the Fox River through education and stewardship.

Collaboration Guided Restoration Efforts

Developing the watershed plan involved broader collaboration. Federal and state agencies, county departments, municipalities, park districts, sanitary districts, and private-sector companies participated in the planning process.

The plan discovered water quality problems requiring attention and outlined specific projects for multiple streams. It also identified responsibility for implementation, estimated project costs, and the expected impact of the projects.

Homeowners’ associations carried out additional projects, although the costs connected with those efforts were not reported.

The combined work generated a substantial amount of restoration activity in the watershed.

27 Projects and More Than $4.8 Million in Work

Over the 10-year period, 27 projects were completed at a total reported cost of $4,800,200.

The accomplishments included naturalization of 157 acres of land. This work included riparian area restoration, detention naturalization, and wetland restoration.

Restoration also covered 16,831 lineal feet of stream.

The projects generated estimated pollutant load reductions of over 2,600 pounds of nitrogen and 1,200 pounds of phosphorus.

The watershed planning effort was also updated in 2025 using new watershed-based plan criteria.

Restoration Produced Measurable Results

Best management practices implemented throughout the Woods Creek watershed resulted in estimated soil savings of 2,554 pounds of nitrogen and 1,221 pounds of phosphorus.

The Woods Creek Watershed-Based Plan also addresses impairments beyond phosphorus. Water quality studies indicated that conditions had generally improved.

The Fox River Study Group analyzed water quality information collected between 2003 and 2016 at the Crystal Creek at the Route 31 site. This location includes the combined Woods Creek and Crystal Creek watersheds.

The analysis discovered that total phosphorus and dissolved phosphorus had decreased over the study period, with declines of 26.6% and 25.5% per year, respectively. Nitrate-nitrogen showed a slight year-over-year increase of 2.2%.

Dissolved oxygen and pH also featured slight decreases over time, consistent with most sampling sites included in the study.

Additional Water Quality Data

Since the original watershed plan was completed, the Illinois Environmental Protection Agency collected additional chemical and physical data within Woods Creek Lake.

Average sample results were reported for chloride, nitrate-nitrite nitrogen, total phosphorus, total suspended solids, conductivity, pH, Secchi disk depth, chlorophyll a, and dissolved oxygen.

Among these parameters, total phosphorus was the only one exceeding criteria guidelines.

Continuing the Work

The improvements in water quality encouraged watershed partners to continue implementing projects identified in the plan and to expand their efforts more broadly.

Partners have adopted and/or supported the Woods Creek Watershed Improvement Plan through resolutions. They have also incorporated its goals, objectives, and recommended actions into comprehensive plans and ordinances.

The Woods Creek experience demonstrates how watershed planning can evolve over time. Beginning with CWA Section 319 funding in 2011, the effort developed into a decade of restoration projects, financial investment, monitoring, and continued collaboration aimed at protecting and improving the watershed.

Source: U.S. Environmental Protection Agency

FAQs:

Q1. What is a watershed?

A watershed is an area connected by the movement of water. Activities within it can affect streams, lakes, and downstream water bodies.

Q2. Why is watershed planning important?

Watershed planning helps identify water quality concerns and organize restoration priorities. It can also guide future projects and funding efforts.