KNOW YOUR AQUIFER

What is PRESENS?

Developed by the ND DWR, PRESENS delivers real-time environmental data from sensors located in remote locations to publicly accessible databases at DWR. Multiple types of data are collected by PRESENS, including water levels, barometric pressure, soil moisture and temperature, precipitation, and air temperature.

Where are PRESENS units located?

History of AEM

Airborne electromagnetic (AEM) surveys were first used in the 1950s in the mining industry. In recent decades, AEM has become more popular in mapping of groundwater resources. States that have used AEM extensively to map groundwater resources are Nebraska, California, and North Dakota.

Why does the DWR collect AEM data?

AEM surveys assist in the mapping of aquifers that help water managers identify and optimize local sources of groundwater.

How does AEM work?

Electrical conductivity is measured with a helicopter carrying a large, suspended wire loop that houses sensors and an instrument package. The loop is flown 100 feet above land surface. The system transmits weak low frequency radio waves into the ground 1,000 feet deep and measures the response that returns from the ground. The surveys are conducted in a grid pattern in order to cover the entire survey area. 

The AEM survey can provide insight into the composition of the earth within the survey area. Clays are typically conductors and aquifer materials such as sand and gravels are resistors.

Where have AEM surveys been conducted in ND?

From 2016-2020, multiple AEM surveys were completed over the Spiritwood, West Fargo, and Wahpeton Valley aquifers.

Future AEM Prospects

States and countries facing similar challenges with groundwater resources as North Dakota are adopting AEM technology. As the technology continues to advance, with improvements in sensor accuracy and data processing, its applications are likely to expand further. We are proud to say that North Dakota has led the way in innovation to identify groundwater resources with the development of PRESENS and a dedicated AEM program.

In the final installment of the Know your Aquifer series, we will talk about water permitting and rights in North Dakota.