Charged about Recharge
Groundwater is water that is pumped up from storage units called aquifers below the Earth’s surface. It is typically used for agricultural irrigation and drinking water. Unfortunately groundwater is being used faster than it can be replaced and recharge is a lengthy process. Groundwater recharge occurs when precipitation infiltrates through the surface into aquifers, this process will transpires at different rates where surfaces are comprised of varying materials. Infiltration happens directly when precipitation flows into streams, rivers and lakes or permeates soil, however, recharge can be inhibited by the ever growing amount of impermeable surfaces. There are many ways that people and communities are attempting to artificially aid in groundwater recharge in an effort to contribute to groundwater sustainability.
Irrigation Innovation
A wide variety of innovations are being approached around the country to enhance the sustainability of important groundwater resources. A combination of storage reservoirs, surface and groundwater use, artificial recharge through wells or surface spreading and the use of recycled or reclaimed water are being put into use. Although these processes may lead to complicated questions of possible negative effects of ground and surface water mixing or degradation of groundwater quality due to introduction of treated water, these attempts recognize the integral necessity of preserving groundwater resources and are a step in the right direction towards achieving sustainability. A few examples of these innovative approaches are discussed below, water resources are becoming increasingly scarce and controversial, educating ourselves, using water responsibly and getting involved are the best tools we can use to preserve this vital resource.
Dayton, Ohio
High-capacity turbine pump installed on a municipal well at Rohrers Island. Recharge lagoon in background.
The population of Dayton, OH is heavily dependent on groundwater resources to meet residential and commercial demand. Much of this water is pumped up through a 30 to 75 foot thick aquifer beneath the Mad River Valley, to ensure that groundwater levels remain high enough to withstand the high capacity drawdowns an artificial recharge system has been in place since the 1930s. Streamflow has been diverted from the Mad River into a series of interconnected infiltration ditches and lagoons that occupy about 20 acres on Rohrers Island. Demand has, of course, increased since the 1930s so, in order to serve the growing demand a municipal well field was installed in the 1960s in a section of the aquifer north of Dayton. In this field water is pumped into a series of recharge ponds and lagoons which double as water hazards on the city-owned golf course.
Wildwood, New Jersey
Wildwood, NJ is a resort town on barrier island on the Atlantic coast in southern New Jersey. As such, the population fluctuates increasing greatly in the summer time, inflating the population size to 30,000 from the its year-round 5,000 inhabitant. The resort town’s water supply is drawn from wells about located about 5 miles inland from the barrier island. Supplying water for the bloated summer population from these wells would require an expensive infrastructure that would not be used for most of the year. To mitigate these costs the Wildwood Water Utility injects groundwater into a shallow aquifer on the island during periods of low demand and withdraws the water in the summer by using dual injection and recovery wells. In operation since 1967, this aquifer storage recovery project (ASR) may be the oldest in the country. ASRs are created when freshwater is injected into a nonpotable aquifer where it can form a high quality water lens for later withdrawal from the same wells. These systems are installed and operated to smooth out annual variability in water demand by recharging aquifers during periods of low demand and recovering the water during periods of high demand. ASRs have a very small footprint and are highly efficient both cost and maintenance wise.
Wildwood beach in summer.
Long Island, New York
Aerial view of Long Island with a visible recharge basin.
The 3 million people who live on Long Island, just outside the New York City metro area, rely solely on groundwater as their source for freshwater. More than 3,000 recharge basins exist throughout the area and together they mitigate stormwater runoff at a rate of 150 million gallons per day, the basins also reduce urban flooding and control saltwater intrusion. Many of these basins were actually abandoned gravel excavation pits but a regulation change in 1936 required developers to design and install recharge basins with the construction of new developments.
