Crystalline rock aquifers can be found under the Olympic Mountains
Washington State residents depend upon groundwater to provide two-thirds of their drinking water. Aquifers play an important role in the water cycle by feeding groundwater to wells and springs through saturated materials and rocks underneath the water table. Aquifers exist in 60 percent of Washington State and can be found close to the surface or plunging 1,000 feet beneath the ground. Scientists have found crystalline rock aquifers composed of igneous and volcanic rock under the Cascade, Olympic and Northern Rocky Mountains of Washington. By using radar technology and geological information, you can find the best areas to search for aquifers in the mountains of Washington State.
Instructions
1. Consult Washington State geologic and topographic maps to identify suitable mountain ranges to focus your search for aquifers. Mountains with an underlying composition of igneous and metamorphic rocks offer a greater probability of yielding crystalline rock aquifers.
2. Locate Washington state aquifers online at the United States Geologic Survey website. There you will find a description of igneous and metamorphic rock aquifers, plus a United States map of igneous and metamorphic rock aquifers at or near the surface. Click on the Pacific Northwest basalt aquifers entry at the bottom of the page to get a detailed map of the Pacific Northwest aquifers.
3. Purchase United States Geologic Survey maps and Washington State topographic maps as references to determine the ground surface area you wish to search, the location of existing basalt rock aquifers and mountain altitudes. Draw your targeted search areas on the maps. Depending upon the location of the mountains, how deep you choose to search and the size of the land to be measured will determine what geophysical radar technology to use.
4. Locate aquifers near the surface in shallow bedrock with Ground Penetrating Radar (GPR). GPR uses microwave pulses of a lower frequency (80 to 500 MHz) to penetrate the ground. Electronic pulses are transmitted into the earth and deflected from the target back to the surface antenna. This technology presents a profile of the location and size of the target object. Pulling the antenna across the surface area you want to measure will create a subsurface picture of the target.
5. Measure large mountain areas quickly in a cost-effective manner with Frequency Domain ElectroMagnetic induction (FDEM). In FDEM an electromagnetic field is created, triggering a current in the ground that causes the earth below the surface to generate a magnetic field. Evaluating the magnetic field yields information about features and soil characteristics.
6. Search for aquifers at a greater depth with Time Domain ElectroMagnetic induction (TDEM). With TDEM, an electromagnetic field is created that triggers a series of currents in the ground designed to penetrate at deeper levels over time. The benefit of using TDEM is the depth at which it can penetrate, thereby profiling much deeper targets.
7. Use the results of your radar surveys to create profiles of targeted mountain areas that show the location of aquifers.
Tags: rock aquifers, Washington State, igneous metamorphic, United States, aquifers near, aquifers near surface, crystalline rock