Lake Bloomington serves as the primary drinking water supply reservoir for the City of Bloomington. Recreation and residential development are the second and third priority uses. It also houses Timber Point Outdoor Center and Camp Peairs, which provide encouraging nature, including forests and shorelines, to children.The roughly 43,000 acre Lake Bloomington watershed is predominately row crop agriculture in corn/soybean rotation with extensive tile drainage. The watershed surrounds both Towanda and Merna. The City of Bloomington and the Town of Normal are expanding into the southwestern edge of the watershed. Money Creek delivers most of the water from the rest of the watershed to Lake Bloomington.
Lake Bloomington Watershed
Watershed ~ 43,100 acres/70 square miles
Lake ~ 570 acre surface area/9.5 miles of shoreline
LAKE BLOOMINGTON WATERSHED SOIL EROSION AND CROPLAND TILLAGE TRANSECT SURVEY
The Illinois Department of Agriculture, in cooperation with Illinois Soil and Water Conservation Districts, completes a Soil Erosion and Cropland Tillage Transect Survey. The survey aims to gather more information about the implementation of conservation farming practices, and to assess the condition of McLean County. Tillage data is gathered for corn and soybeans, and the county’s T levels are assessed. “T” represents the tolerable soil level loss, or the amount of soil that can be replaced naturally by the decomposition of crop residue. In addition to T levels and tillage data, the survey compiles some information on cover crop use.
Agricultural runoff is a significant source of phosphorous and nitrate-nitrogen loading into Illinois waterways. Nutrient runoff is carried by the rivers and streams to the Mississippi, and down to the Gulf of Mexico. Nutrient concentration in the Gulf of Mexico is so high that it causes algal blooms, and subsequent dead zones called “hypoxic zones”, devoid of life. To combat this issue and promote soil health and water quality, Illinois’ Nutrient Loss Reduction Strategy (NLRS) was created. The NLRS aims to direct efforts to reduce nutrients from point and non-point sources. The goal is for Illinois to reduce its phosphorous load by 25% and its nitrate-nitrogen load by 15% by 2025. The eventual target is a 45% reduction in the loss of these nutrients to the Mississippi River.
Some conservation practices that help reduce nutrient runoff include cover crops, filter strips and buffers, conservation tillage (no-till, strip-till, etc.) and habitat projects, such as pollinator habitat and constructed wetlands .
LAKE BLOOMINGTON WATERSHED TRANSECT SURVEY RESULTS
The latest Lake Bloomington Transect Survey was conducted on 105 McLean County field locations. Comparable to prior surveys these results suggest a decrease in no-till and increase in conventional tillage practices. Results on corn acres showed 45% Conventional Till, 30% Mulch Till, 23% Reduced Till, and 2% No-till. Soybean acres resulted in 49% Mulch Till, 39% No-Till, 7% Conventional, and 5% Reduced Till. The cumulative figures were as follows: 105 locations measured, 18 No-Till fields, 39 Mulch Till fields, 16 Reduce Till fields, and 30 Conventional fields. No Cover Crop residue was found.