Groundwater Management

Another significant activity area concerns groundwater management and protection of the Garber-Wellington aquifer. The Garber-Wellington Association (GWA) implements programs and policies dedicated to these tasks. Established in 1979, the GWA is an association of the local government beneficiaries of the Garber-Wellington aquifer.

The Garber-Wellington Aquifer

The Garber-Wellington formation is the major acquifer in Central Oklahoma. Roughly 280 million years old, this geologic unit was formed by ancient river systems that deposited as much as 1000 feet of sandstone and shale over this area. The rivers flowed from east to west. They deposited the now water bearing sediments over a broad, flat coastal plain and in deltas that extended into an inland sea that lay to the west. The water bearing portion of the Garber-Wellington formations outcrops in a north-south band from the Cimarron to the Canadian River across Central Oklahoma.

Generalized Surface Geology

	Unit Name	Lithology
	No Recharge Hennessey Shale	Shale
	Good Recharge Garber Sandstone	Sand
	Fair Recharge Wellington Formation	Shaly Sand

Groundwater Technical Guidance

GWA staff provides continuing coordination and assistance to local governments for their groundwater systems and research efforts. One of the most important groundwater resources in the state, a large population in Central Oklahoma relies upon the aquifer for potable water. Staff of the GWA provides technical guidance to local government members in managing, expanding and protecting their groundwater systems. This includes providing technical maps and analyses for well site location, water level surveys and water chemistry sampling.

Water Quality Analysis and Monitoring

For more than 15 years, GWA staff has conducted a comprehensive water quality and quantity monitoring program. Municipal well sampling programs are conducted to determine if changes in water quality and water characteristics have occurred.

ACOG maintains a computerized database of current and historical municipal sampling data. The database is the most comprehensive collection of technical data on the Garber-Wellington aquifer, drawing from collection activities at state and federal levels, as well as from municipal-level aquifer management programs.

Land Use Management

The Garber-Wellington Association encourages proper land use management in the recharge area of the Garber-Wellington aquifer for those entities that have planning and zoning jurisdictions. Land use practices outside those areas should be monitored as part of the implementation of wellhead protection activities.

Staff also advises the local communities to the placement and density of septic tanks and sewage lagoon systems to avoid concentrated areas of nitrate in the groundwater system.

Legislative Activities

GWA staff also actively participates in municipal efforts to improve the effectiveness of their oil and gas drilling ordinances. Specific recommendations to update these ordinances include more stringent oil and gas well abandonment procedures and downgrading monitoring wells for saltwater injection and waterflood operations.

A model oil and gas ordinance was developed by the GWA. This ordinance provides municipalities with the ability to protect the health and safety of their citizens, protect the groundwater supplies, and provide for inspection of drilling and production activities within their boundaries. Twenty-two local governments in the ACOG region currently enforce oil and gas ordinances based on this model ordinance.

Water Well Construction/Design Assistance

Water well construction and spacing recommendations are part of the site location analysis that GWA staff performs. This is necessary for optimum water production and water quality. As local governments expand their well fields, new wells incorporate these designs.