Groundwater Quantity Rules & Regulations

In general, the Lower Platte North NRD has an adequate supply of groundwater. However, history shows that extended drought and/or excessive water use could deplete our groundwater below useable levels. To guard against this possibility, the NRD measures district groundwater levels twice a year, and has installed dedicated monitoring wells in selected areas. (The most recent groundwater level results can be viewed here.)

For monitoring groundwater quantity, the district has been divided into several subareas with similar aquifer conditions (see map below). Within each subarea, a control area may be established if more than 50% of the district's monitoring wells reach or fall below the "trigger level."

The trigger level varies depending on the type of aquifer: confined or unconfined. (An aquifer is a underground layer of material, such as sand or gravel, that is saturated with water.)

Unconfined Aquifers

Unconfined aquifers are not sealed off from the ground surface and have the same pressure as the atmosphere. Therefore, the water table (the upper surface of the saturated zone) is free to rise and fall according to groundwater recharge and the amount of water withdrawal through wells. A well drilled into an unconfined aquifer will often show these fluctuations. When water withdrawal exceeds recharge, water levels may fall below the bottom of the well, rendering it dry.

Trigger levels are more lenient for unconfined aquifers, because these aquifers are not prone to land subsidence if too much water is removed.

Confined Aquifers

Confined aquifers are aquifers that are sealed off by a confining layer made up of impermeable material such as clay that prevents or slows water movement into the aquifer. Confined aquifers are under pressure, so when a well is drilled into one, water will tend to rise in the well casing. In some cases, water could rise all the way to the ground surface. This is referred to as a "flowing artesian well."

If too much water is removed from a confined aquifer, land subsidence can sometimes result, creating sinkhole-like conditions. The storage capacity of the aquifer can also be reduced, sometimes permanently.

Aquifer Diagram

Rules & Regulations

Unconfined Aquifers
Rules & Regulations	Level 1 (10% Drop in Saturated Thickness)	Level 2 (15% Drop in Saturated Thickness)
Education classes and certification every 4 years for operators of irrigation, municipal, and industrial well systems.	Required	Required
Permits for all new wells with a capacity greater than 50 gallons per minute.	Required	Required
Well metering program for all irrigation, municipal, and industrial wells.	Encouraged	Required
Acre-inch allocations per crops planted, dependent on aquifer.	Encouraged	Required
Annual water use report made to NRD before Dec. 31 every year.	Encouraged	Required
Well spacing restrictions observed (varying with percent of decline).	Encouraged	Required
Best management practices used.	Encouraged	Required

Confined Aquifers
Rules & Regulations	Level 1A (7% drop in potentiometric aquifer thickness)	Level 2A (10% drop in potentiometric aquifer thickness)	Level 3A (15% drop in potentiometric aquifer thickness)
Education classes and certification every 4 years for operators of irrigation, municipal, and industrial well systems.	Required	Required	Required
Permits for all new wells with a capacity greater than 50 gallons per minute.	Required	Required	Required
Well metering program for all irrigation, municipal, and industrial wells.	Encouraged	Required	Required
Acre-inch allocations per crops planted, dependent on aquifer.	Encouraged	Required	Required
Annual water use report made to NRD before Dec. 31 every year.	Encouraged	Required	Required
Well spacing restrictions observed (varying with percent of decline).	Encouraged	Encouraged	Required
Best management practices used.	Encouraged	Encouraged	Required

More Information

If you have questions or would like more information about the GWMA, please contact Water Resources Manager Larry Angle.