Crystal Lake Watershed

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Aerial of Crystal Lake 
The City’s namesake, Crystal Lake, is an important and environmentally sensitive resource that requires vigilance to keep it a high quality lake. The lake is a popular recreation destination, providing opportunities such as swimming, boating and fishing in the summer and ice-skating in the winter. The area around Crystal Lake that drains to the lake is called the Crystal Lake Watershed. The City has special requirements that regulate development and land use in the watershed, which helps protect the quality and quantity of water that reaches the lake.

 

What Is the Crystal Lake Watershed?
The Crystal Lake Watershed is an area of approximately 2300 acres of land, primarily north of the lake. Crystal Lake is unique among many other lakes in the area, as its water does not come from a spring nor is the lake fed by a stream or river. The lake is fed by a variety of sources:

  • The Lippold Field drainage tile (pipe)
  • Drainage from Cove Pond
  • Direct precipitation on the lake
  • Groundwater that percolates from shallow underground aquifers
  • Direct surface runoff

This means that the lake is sensitive to changes in stormwater quality and volume in its watershed. Most of the land in the watershed is currently undeveloped, and is used for either farmland or open space. There is also a substantial urbanized area in the watershed.

History of Watershed Protection
Regulation of the Crystal Lake Watershed began in the mid 1970s. A study called the “Crystal Lake Watershed Resources Management Study” identified ways to maintain the quality and volume of water recharging the lake, such as limiting the amount of impervious surfaces, (i.e. parking lots and driveway), and not allowing any new septic tanks to be built. The City adopted these recommendations in 1975 as the first Crystal Lake Water Watershed Management Ordinance, and they have been in place since that time. At the time, the approach of managing an entire watershed with a single plan was innovative, and other governmental agencies have since begun to use watershed management planning as a viable way of preserving and enhancing water resources.

Crystal Lake Watershed Design Manual & Implementation Plan
In 2005, thirty years after the original ordinance was adopted, the Mayor and City Council appointed an ad hoc technical advisory committee to examine the watershed regulations, and recommend any changes they deemed appropriate. Since the original watershed ordinance was adopted, there have been advances in stormwater management and understanding of the Crystal Lake Watershed itself. With the help of a highly skilled water resources consultant, the technical advisory committee completed a two year study of the watershed and made recommendations on how the watershed regulations could be updated to allow for more effective protection of Crystal Lake and its watershed. This study was called the “Crystal Lake Watershed Design Manual,” and had many new recommendations about how the watershed could be managed more effectively.

In late 2007, the Mayor and City Council spent considerable time critiquing the “Crystal Lake Watershed Design Manual.” This led to the “Design Manual Implementation Plan,” which is a companion document that provides details about how BMPs used in the watershed will be monitored to ensure they are working properly and maintained in perpetuity. The City Council then officially adopted the Design Manual and the Implementation Plan by ordinance as a guide on how the watershed will be managed.

The most significant change in the management of the Crystal Lake as established in the Design Manual is that now more impervious area can be included in a development, but the developer must design BMPs that are effective at ensuring the water percolates into the ground. In addition, the Design Manual also requires that any new development have some sort of treatment of stormwater runoff to remove pollutants, such as phosphorus.

For more information on the Crystal Lake Watershed, including what you can do to help it, download this brochure about the Crystal Lake Watershed.

Site Improvements to Single Family Residential Homes in the Crystal Lake Watershed

If an improvement to your home or lot (house or garage addition, new garage, shed, patio, sidewalk, or new or widened driveway) increases the amount of impervious area, a trench drain may be required. City staff in the Engineering Division will determine if a trench drain is required but the following provides general guidelines.

If the additional square footage of impervious area for the improvement is less than 300 square feet, a trench drain is not required. If in the future there is additional impervious area added to the lot, it will be added to this impervious square footage and the cumulative number will be used to determine if a trench drain will be required.

If the impervious area is more than 300 square feet, a trench drain will need to be installed to compensate for the additional impervious area. In lieu of infiltration calculations provided by licensed Professional Engineer to determine how many feet of trench drain would be required, the City requires a minimum of 1 foot of trench drain per every 50 square feet of additional impervious area. A trench drain is required to be a minimum of 25 feet from a structure. 

Here is the City's standard detail for a trench drain.

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