💧     The City of Wichita Public Works & Utilities department supplies drinking water to residents and wholesale customers primarily from two sources: Cheney Reservoir (60%) and the Equus Beds Aquifer (40%). The utility is currently navigating a major multi-million-dollar infrastructure overhaul while maintaining strict year-round conservation rules.

Cheney Reservoir is the cornerstone of Wichita’s municipal water system, typically supplying 60% to 70% of the city's drinking water. Located roughly 20 miles west of the city on the North Fork of the Ninnescah River, the reservoir acts as the city's primary surface water source, balanced alongside the underground Equus Beds Aquifer.

🧪 Water Quality: Algae & Agricultural Runoff

Because the reservoir relies on a massive watershed dominated by agriculture, water quality is highly vulnerable to upstream runoff.

• Algae Blooms: Cheney Reservoir regularly battles cyanobacterial (blue-green algae) blooms. While treated water remains completely safe to drink, these blooms produce compounds like geosmin, which cause occasional earthy or musty tastes and odors in city tap water.
• Runoff Pollutants: High concentrations of phosphorus and suspended sediment from nearby farms flow into the lake, designating the reservoir as "impaired" by the state

The Equus Beds Aquifer is a massive 900,000-acre underground water reserve in south-central Kansas that spans parts of Harvey, McPherson, Reno, and Sedgwick counties. Managed by the Equus Beds Groundwater Management District No. 2 (GMD2), it acts as the primary source of fresh water for roughly 600,000 people, supplying municipal water to Wichita and Hutchinson, while driving the region's agricultural irrigation.

 🧪  Water Quality: Complications with contaminants in the Equus Beds Aquifer revolve around a mix of historic industrial pollution, modern agricultural practices, and natural geological threats. Because Wichita and other regional communities rely heavily on this aquifer, these contaminants present significant economic, infrastructural, and public health hurdles.

The single largest threat to Wichita’s well fields is a massive underground plume of high-chloride brine near Burrton, Kansas.

• The Cause: Oil and gas production between the 1920s and 1950s utilized unlined evaporation pits, which allowed millions of gallons of highly concentrated saltwater to sink into the soil.
• The Complication: The Kansas Water Office (KWO) warns that this plume is migrating east-southeast directly toward Wichita’s municipal wells. If it reaches them, the water will become completely unusable as a drinking source or for crop irrigation without extremely expensive, large-scale desalination.

🪨 Naturally Occurring Arsenic

Arsenic is heavily present within the natural clay layers of the aquifer's geology.

• The Complication: Long-term exposure to arsenic is a serious human health hazard. The U.S. Geological Survey (USGS) noted that arsenic exceeds the EPA’s Maximum Contaminant Levels (MCL) in roughly 12% of shallow wells and up to 35% of deep wells across the aquifer. This requires precise, continuous monitoring during municipal water treatment.

🚜 Agricultural Herbicides & Fertilizers (Atrazine & Nitrates)

Because the land overlying the 900,000-acre aquifer is dominated by commercial farming, agricultural chemicals frequently leach into the water supply.

• Atrazine: This widely used corn herbicide does not naturally occur in the environment but is highly prevalent in the surface water used to artificially recharge the aquifer.
• Nitrates: Heavy fertilizer application has caused elevated nitrate concentrations, which are primarily concentrated in the shallowest parts of the aquifer (particularly in the southeastern region). High nitrates pose a strict risk to infants and pregnant women ("blue baby syndrome").

 🌊Natural Saltwater Intrusion from the Arkansas River

Human activity is actively changing how the aquifer moves, introducing a second source of saltwater.

• The Complication: High-volume pumping for city use and crop irrigation has lowered the local water table. According to historical Kansas Geological Survey field observations, lowering the freshwater table has allowed natural, heavy saltwater from the nearby Arkansas River to bypass geographical barriers and penetrate deeper into previously clean freshwater zones.

🛡️ How Wichita Fights Back: The ASR Complication

To keep the chloride plumes at bay, Wichita treats surface water from the Little Arkansas River and pumps it into the ground to create a "freshwater wall" (the Aquifer Storage and Recovery or ASR project). However, this solution introduces its own chemical complications:

• The Balancing Act: The river water being forced underground is heavily contaminated with seasonal Atrazine and bacteria. Wichita must aggressively treat this surface water before injection so it doesn't accidentally ruin the pristine portions of the aquifer.