Report: Changing climate, land use will impact county’s water use

Climate change and increased land use will affect how McHenry County manages its water supply and preserves it for future years, according to a new report published online Wednesday by the McHenry County Department of Planning and Development.

The Water Resources Action Plan describes how McHenry County uses water and different ways to conserve water. It also outlines how changes to the landscape such as urbanization and severe weather events as a result of climate change will affect water in the county.

The plan previously was developed in 2011 and work to update it began in 2018 to address changes over the past decade in the county. It was approved by the County Board last year.

“Midwestern cities, suburbs and rural areas are projected to be more exposed to negative impacts of climate change,” the report states.

The report includes a pair of graphics showing how the climate in northeast Illinois has changed since 1900. Over the past 120 years, the annual amount of precipitation has increased by 5%, and the average temperature for the year has increased by 1.5 degrees.

“It is not just the amount of precipitation that has increased: the intensity of the storms is increasing as well. The increased precipitation is occurring in fewer storms, as more precipitation falls in each of these events. The increasing volume and intensity of precipitation events can overwhelm the soil’s ability to absorb water and the existing infrastructure, which was designed at a time when precipitation rates were lower,” the report states.

Some communities will need to make infrastructure changes to address the issue of higher intensity rainfalls to prevent flash flooding, according to the report.

Droughts also will be a factor even though the county is receiving more rainfall.

“In addition to increased precipitation in the winter and spring, the Midwest will also likely experience a higher number of consecutive dry days between storm events, resulting in prolonged periods of drought,” the report states.

The rising temperatures also factor into how much water is available. With temperatures rising, evaporation rates also increase, according to the report, causing sources of water to dry up faster.

McHenry County is dependent on groundwater, specifically sandstone and bedrock aquifers. The report issued a warning for the county that water from these sources may no longer be an option in 30 years.

“Based on the amount of water currently being pumped from the deep sandstone aquifers, all of southeast McHenry County is at risk of declining well performance; and some communities face severe risks of well inoperability as early as 2050.”

The report states communities need to start considering alternative sources of water now to avoid expensive projects in the future and meet future demands, which, according to the Chicago Metropolitan Agency for Planning, could be 24% to 30% higher than they are now.

This could bring the county’s two watersheds into play. All of the county’s water drains into the Kishwaukee and Fox rivers. While they are not used by any of the McHenry County municipalities, some towns downstream on the Fox River use it for drinking water, which means it could be a future water source as towns look for alternatives to the aquifers, according to the report.

How the land is used also plays an important role, especially urbanization. Areas with more construction make it more difficult for water to drain into the ground, causing issues with flooding. This is particularly true in communities along the Fox River where buildings were constructed in the flood plain before the flood plain was mapped, according to the report.

More industrialization and urbanization also increase the amount of pollutants in ground water and local rivers, according to the report. Rainwater runs off into these water sources, carrying the pollutants with it. Polluting drinking water sources, such as through salt on the roads in winter or fertilizer on lawns, can happen easily, according to the report.

Understanding how land will be used in the county in the future is key to planning water usage, according to the report. With significant development likely happening in the eastern half of the county, the report found 18% of McHenry County’s land will be deemed “environmentally sensitive” by 2030.

While the changing climate and ways land is used in McHenry County present challenges for the future and the need to explore alternative water sources, the report says that many of the problems can be addressed now by individuals.

Municipalities can take action by directing residents on how to use water, such as through specific irrigation periods in neighborhoods. However, the report also includes recommendations for people to conserve drinking water, such as fixing leaks and not letting water run without a purpose while doing the dishes or taking showers.

The full report can be viewed at www.mchenrycountyil.gov/county-government/departments-j-z/planning-development/water-resources.