SOURCE WATER ASSESSMENT SUMMARY

The Village of Cary (Facility Number 1110100) utilizes nine active community water supply wells. Wells #3, #4, #6, #8, #9, #10, #11, #12, and #13 (Illinois EPA #20138, #20139, #20141, #20142, #00306, #20144, #00705, #00952, #01428 respectively) produce approximately 1.5 million gallons per day delivered to 6,100 service connections and serve an estimated population of 18,271 individuals in Cary. To determine Cary's susceptibility to groundwater contamination, the Illinois EPA’s Well Site Survey, published in 1989, and Baxter and Woodman’s Groundwater Protection Needs Assessment, first published in 1992 and revised in 1999, were reviewed.

During the surveys of Cary's source water protection area, potential sources, routes, or possible problem sites within the 200 or 400 foot minimum setback zones, 1,000 foot maximum setback zones, and recharge areas were recorded. No sources are located within any of the minimum setback zones of Cary’s wells. There are four sources located in the proposed maximum setback zone around wells #8 and #9. There are also four sources located in the proposed maximum setback zone around well #6. Within the recharge areas, two sources are located in the recharge area for wells #10, #11, and #12. Numerous sources were located in the recharge area for wells #3, #8, and #9. The Illinois EPA considers the source water of this facility to be susceptible to contamination. This determination is based on a number of criteria including: monitoring conducted at the wells, monitoring conducted at the entry point to the distribution system, the available hydrogeologic data on the wells, and the land-use activities in the recharge area of the wells.

The Illinois Environmental Protection Act established minimum protection zones of either 200 or 400 feet for Cary’s active community water supply wells. These minimum protection zones are regulated by the Illinois EPA. In addition, as part of Baxter and Woodman’s Groundwater Protection Needs Assessment, recharge areas for wells #3, #8, #9, #10, #11, and #12 have been delineated. A recharge area is the geographic area surrounding a well or well field providing potable water to a community water supply as modeled using computer software to determine a five-year time of travel.

To further minimize the risk to the Village’s water supply, the Illinois EPA recommends that the following activities be assessed. First, the supply may wish to petition the Village of Cary to enact a maximum setback zone ordinance. These ordinances are authorized by the Illinois Environmental Protection Act and allow county and municipal officials the opportunity to provide additional protection up to 1,000 feet from their wells. Second, the Illinois EPA recommends that Cary adopt a wellhead protection plan to reduce the risk of contamination to the water supply. Third, the Village of Cary should establish a regulated recharge area and develop and implement a recharge area management plan. However, this would require a cooperative effort with other local political bodies because the recharge area around wells #10, #11, and #12 extends beyond the Village of Cary corporate limits and into McHenry County, Algonquin, and Lake in the Hills. In April of 2011, the Village completed one of the EPA’s recommendations by properly filling and sealing Well #5 which had been inactive for years. Inactive wells that are not properly abandoned (filled and sealed) can act as direct conduits into the aquifer which may allow surficial contaminants to enter the water supply and are considered "potential routes" of contamination under the Environmental Protection Act.

In addition to source water contamination prevention, Cary should also consider the following efforts to protect the finished water supply. First, a cross connection control ordinance should be adopted and a program designed to implement the ordinance. Cross connections to either the water treatment plant (for example, at bulk water loading stations) or in the distribution system may negate all source water protection initiatives provided by the supply. Second, contingency planning documents should be developed to ensure the water department and emergency response staff are aware of and adequately trained to implement emergency procedures. Contingency planning documents are a primary means to ensure that, through emergency preparedness, a water supply will minimize their risk of being without safe and adequate water.