The Spokane Valley–Rathdrum Prairie (SVRP) Aquifer is an

aquifer An aquifer is an underground layer of water-bearing material, consisting of permeability (Earth sciences), permeable or fractured rock, or of unconsolidated materials (gravel, sand, or silt). Aquifers vary greatly in their characteristics. The s ...

in the

northwest The points of the compass are a set of horizontal, radially arrayed compass directions (or azimuths) used in navigation and cartography. A '' compass rose'' is primarily composed of four cardinal directions—north, east, south, and west— ...

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

, underlying 370 square miles in

eastern Eastern or Easterns may refer to: Transportation Airlines *China Eastern Airlines, a current Chinese airline based in Shanghai * Eastern Air, former name of Zambia Skyways *Eastern Air Lines, a defunct American airline that operated from 192 ...

Washington Washington most commonly refers to: * George Washington (1732–1799), the first president of the United States * Washington (state), a state in the Pacific Northwest of the United States * Washington, D.C., the capital of the United States ** A ...

and

northern Northern may refer to the following: Geography * North North is one of the four compass points or cardinal directions. It is the opposite of south and is perpendicular to east and west. ''North'' is a noun, adjective, or adverb indicating ...

Idaho Idaho ( ) is a landlocked U.S. state, state in the Pacific Northwest and Mountain states, Mountain West subregions of the Western United States. It borders Montana and Wyoming to the east, Nevada and Utah to the south, and Washington (state), ...

."Spokane-Rathdrum Prairie aquifer". ''Spokesman-Review''. (Spokane, Washington). (map). February 24, 1980. p. B6. The aquifer is centralized under

Spokane Valley The Spokane Valley is a valley of the Spokane River through the southern Selkirk Mountains in the U.S. state of Washington (state), Washington. The valley is home to the cities of Spokane and its suburbs Spokane Valley, Washington, Spokane Vall ...

and the

Rathdrum Prairie The Rathdrum Prairie is a flat in the U.S. state of Idaho. The prairie contains the cities A city is a human settlement of a substantial size. The term "city" has different meanings around the world and in some places the settlement can be ...

, hence the name, and is part of the

Columbia River drainage basin The Columbia River drainage basin is the drainage basin of the Columbia River in the Pacific Northwest region of North America. It covers . In common usage, the term often refers to a smaller area, generally the portion of the drainage basin tha ...

. It is composed of unconsolidated gravels, cobbles, and boulders deposited during the glacial flooding of Lake Missoula.Spokane County. "Spokane Valley-Rathdrum Prairie Aquifer". ''spokanecounty.org''. Spokane County. Retrieved 16 November 2023."Compilation of Information for Spokane Valley–Rathdrum Prairie Aquifer, Washington and Idaho". ''USGS''. U.S. Department of the Interior. Retrieved 16 November 2023. The aquifer is highly permeable and in direct contact with the surface, so there is a high interchange rate between

surface water Surface water is water located on top of land, forming terrestrial (surrounding by land on all sides) waterbodies, and may also be referred to as ''blue water'', opposed to the seawater and waterbodies like the ocean. The vast majority of surfac ...

and the aquifer. The

Spokane River The Spokane River is a tributary of the Columbia River, approximately long, in northern Idaho and eastern Washington in the United States. It drains a low mountainous area east of the Columbia, passing through the Spokane Valley and the city o ...

and

Little Spokane River The Little Spokane River is a major tributary of the Spokane River, approximately long, in eastern Washington in the United States. It drains a rural area of forested foothills and a farming valley north of the city of Spokane along the Idaho– ...

lie directly above the aquifer and receive aquifer outflow. The area surrounding it receives an average of 15–30 inches (38–76 cm) of rain annually. The aquifer is the primary water source for the greater Spokane area.

Productivity

The Spokane Valley–Rathdrum Prairie Aquifer is one of the fastest and most productive aquifers in the country. The volume of the aquifer is about ten trillion gallons (38 trillion liters) of water. It supplies water to over 500,000 people in the Spokane region, producing an average of 146 million gallons of water each day. The coarse-grained materials that make up the aquifer contribute, in part, to the aquifer’s high productivity and velocities of up to 60 feet per day. The high interexchange rate between the SVRP Aquifer and groundwater flow also contributes to its high recharge and flow rates.

Contamination

The Spokane Valley-Rathdrum Prairie (SVRP) Aquifer is unconfined and has no protective layer, which makes it vulnerable to contamination from a variety of pollutants. As a result, many local organizations monitor water quality in the aquifer and investigate potentially dangerous contaminants.''“The Spokane Valley-Rathdrum Prairie Aquifer Atlas Fifth Edition.�

' Accessed 13 Nov. 2023. A 1988 technical report of the aquifer from the Idaho Department of Health and Welfare investigated and ranked 14 potential contaminants. In order from greatest to least potential for contamination, these contaminants included: Agricultural pollution, agriculture,

petroleum Petroleum, also known as crude oil or simply oil, is a naturally occurring, yellowish-black liquid chemical mixture found in geological formations, consisting mainly of hydrocarbons. The term ''petroleum'' refers both to naturally occurring un ...

landfill A landfill is a site for the disposal of waste materials. It is the oldest and most common form of waste disposal, although the systematic burial of waste with daily, intermediate and final covers only began in the 1940s. In the past, waste was ...

hazardous materials Dangerous goods are substances that are a risk to health, safety, property or the Natural environment, environment during transport. Certain dangerous goods that pose risks even when not being transported are known as hazardous materials (syll ...

, subsurface sewage disposal systems,

surface runoff Surface runoff (also known as overland flow or terrestrial runoff) is the unconfined flow of water over the ground surface, in contrast to ''channel runoff'' (or ''stream flow''). It occurs when excess rainwater, stormwater, meltwater, or other ...

dry well A dry well or soak is a structure formed underground that disposes of unwanted water, such as surface runoff water and stormwater. In this process, the water is infiltrated into the ground, further merging with groundwater in the local area. Th ...

s, industrial wastewater, land application of septage and sludges, pits, ponds and lagoons,

dairies A dairy is a place where milk is stored and where butter, cheese, and other dairy products are made, or a place where those products are sold. It may be a room, a building, or a larger establishment. In the United States, the word may also des ...

and

feedlot A feedlot or feed yard is a type of animal feeding operation (AFO) which is used in intensive animal farming, notably beef cattle, but also swine, horses, sheep, turkeys, chickens or ducks, prior to slaughter. Large beef feedlots are called conc ...

s, radioactivity,

silvicultural Silviculture is the practice of controlling the growth, composition/structure, as well as quality of forests to meet values and needs, specifically timber production. The name comes from the Latin ('forest') and ('growing'). The study of forests ...

activities, well drillings, and mining.Jehn, Paul. “The Rathdrum Prairie Aquifer Technical Report.” ''Idaho Department of Environmental Quality.'' https://www2.deq.idaho.gov/admin/LEIA/api/document/download/4680 Accessed 16 Nov. 2023. Aboveground fuel tank farms are also a concern. Within the aquifer's watershed, several fuel tank farms house thousands of gallons of fuel for companies like Exxon-Mobil. If not properly constructed, monitored, and used, these tanks could burst, contaminating the nearby communities’ source of drinking water as fuel seeps through the ground and into the aquifer. In 1978, the SVRP Aquifer became the second aquifer designated as a "sole source aquifer" by the EPA. Protecting and maintaining the aquifer's quality is considered critical by the community. Several programs have been recommended to preserve the aquifer, including education, monitoring, management, and regulation.

Aquifer-Spokane River Interaction

One unique aspect of the SVRP Aquifer is its interaction with the Spokane River. The two water bodies share a cycle of gaining and losing water to each other, and this function is important to both the river and the aquifer. The Spokane River receives about 59% of the water that exits the aquifer. At the same time, it is also the greatest source of inflow to the aquifer. This water interchange occurs in a series of gaining reaches and losing reaches of the Spokane River. In the gaining reaches of the river, the surface level of groundwater in the aquifer is above the bottom of the river. This causes water to flow from the aquifer into the river. On the other hand, losing reaches occur when the river bottom is above the aquifer’s water level, resulting in a transfer of water from the river to the aquifer.

References

External links

City of Spokane Public Works and Utilities
{{DEFAULTSORT:Spokane Valley-Rathdrum Prairie Aquifer Aquifers in the United States Geography of Spokane, Washington Coeur d'Alene, Idaho