This is why the Forest Service should lead the way in sustainable groundwater management
Posted August 6, 2014
Do you live in or near a National Forest or Grassland? Do you camp, fish, or paddle in one? Do you just like to know you have access to 193 million acres of forestland filled with wetlands, streams, and lakes? If so, take note of a proposed Forest Service policy that is designed to help keep waters flowing on and around these forests.
Isn’t this what we would all expect our natural resource managers to do with public water? To track and restore this resource for future generations. In fact, the establishing Act for the United States Forest Service states that, “No public forest reservation shall be established, except to improve and protect the forest within the reservation or for the purpose of securing favorable conditions of water flows…”
Why do our streams and rivers need groundwater?
Groundwater provides a number of services few of us are even aware of: water storage; natural water purification of potentially harmful metals, nutrients, and pathogens; erosion regulation and flood control. Shallow aquifers maintain water levels in wetlands, and meadows, springs, and rivers - called groundwater dependent ecosystems. Healthy groundwater levels can provide a stable water resource during times of drought, sustaining streamflows and contributing to water supplies. In the U.S. more than 95% of rural populations depend on aquifers to provide some portion of their drinking water.
Groundwater dependent bull trout (U.S. Forest Service)
One of the most promising aspects of the proposed groundwater policy is the recognition that the vast majority of our rivers and lakes are physically connected to waters underground. This would be one of the first federal policies of the kind, offsetting a false dichotomy in place in many areas where surface and groundwater are managed separately.
Think of it like this. Fill a bucket with water and place a sponge full of water in that bucket. Some water may seep out of the sponge into the bucket like groundwater into a lake. Now imagine someone removes the sponge from the bucket and wrings it out. When the sponge is put back in the bucket it sucks up the water in the lake - this is analogous with the impacts of groundwater pumping on streams and lakes. Assuming the sponge and bucket of water are separate just doesn't make sense.
Managing surface and groundwater resources as a unified whole is critical in National Forests, where the headwaters of many great rivers are found – declining groundwater levels on these lands would decimate their flows and their value to visitors and ecosystems. Including groundwater in planning efforts on National Forests will benefit fishing and recreation on and around important rivers and springs throughout the country, such as Juniper Springs in Ocala National Forest, Jordan Hot Springs on the Gila National Forest, Rock Creek in the Yolo National Forest in Montana, the upper White River in the White River National Forest in Colorado, the South Fork of the Trinity River and in the Shasta-Trinity National Forest and the nearby Scott River in California. These are only a few examples.
The map below shows the percent of streamflow that comes from groundwater. Many of the darkest blue areas, where groundwater is most important are on National Forests in the Pacific Northwest and Rocky Mountains. Many other National Forests contain groundwater resources that support at least half of streamflows. What would happen if we lost access to these resources? At the very least, many streams would no longer provide adequate fishing or recreational opportunities.
Why do we need the Forest Service (and other agencies) to implement this policy now?
The fact is that we know very little about the amount or quality of groundwater that is used or is available, which has led to severe groundwater level declines in many parts the U.S. From 1900 – 2008, USGS estimates that approximately 810 million acre feet of groundwater volume has been depleted in the United States. In perspective, that volume of water would cover the entire state of Pennsylvania in about 27 feet of water. It would be commonsense for state and federal agencies to protect valuable groundwater resources now. Without protection, falling groundwater levels will mean:
Less water in streams and lakes: According to estimates from the U.S. Geological Survey, on average, groundwater makes up 40-50% of the flow in small and medium streams throughout the country. It is not uncommon for groundwater pumping to leave streams completely dry when water demand is high, eliminating or interfering with fish migration and spawning.
Deterioration of water quality: Declining groundwater levels can leave less water in lakes and rivers, concentrating pollutants and in some cases polluted groundwater discharges back into streams. In coastal areas, removing groundwater from underground allows saltwater to seep in, killing sensitive wetland plants and animals and making water unfit to drink.
Land subsidence: Pulling water from aquifers without recharge leaves an empty space underground, and like an éclair without the filling, the land above the aquifer eventually sinks or collapses, wiping out its natural water storage capacity.
Declining forest productivity: Falling groundwater levels disconnect riparian trees from their water sources, decreasing productivity and increasing risk from fires and disease.
Rising Costs and Pollution: Falling groundwater levels means we need deeper wells or stronger pumps to access water underground, increasing the monetary and energy costs of accessing this water. This affects millions of landowners who depend on groundwater wells and much of the agricultural industry.
We are encouraged by the Forest Service’s leadership to protect instream flows and wetlands, provide water downstream for water users who need it, and ensure no net depletion of groundwater resources on National Forest lands. Such action will help ensure our public waters are available for current and future generations. In a future blog, I will discuss how we think the proposed policy can be improved to better protect our groundwater.