The Southwest Florida Water Management District Governing Board Tuesday concurred with an emergency authorization allowing the Peace River/Manasota Regional Water Supply Authority (Authority) to utilize its existing Aquifer Storage and Recovery (ASR) wellfields for the temporary production of ground water to meet regional demand.
The Authority’s ASR wellfields are normally used to store excess treated surface water from its permitted Peace River withdrawals for later use. The Authority’s existing permit only allows for it to pump previously injected water from this aquifer storage.
However, the ongoing drought has depleted the ASR reserve supplies. The emergency order signed last week by the District’s executive director, David Moore, allows the Authority to draw native ground water from the ASR wellfields to mitigate the effects of the ongoing drought on the public water supply.
The Authority’s service area includes North Port as well as Charlotte, DeSoto, Sarasota and Manatee counties (Manatee County currently does not receive water from the authority).
The authorization will allow the Authority to temporarily utilize its existing ASR wellfields for the production of ground water, with a maximum groundwater withdrawal rate of 17.0 million gallons per day.
Groundwater production may only commence when ASR storage is exhausted and shall cease no later than July 1, 2008. It must also be temporarily suspended any time the Authority is able to meet demand using its other water sources.
The Peace River is the Authority’s primary water source to meet the drinking water needs of approximately 250,000 residents in a four-county region. During periods of high river flows, the authority typically stores water in its reservoir and two ASR wellfields for later use during the dry season or whenever river withdrawals are not sufficient to meet drinking water demands.
As of March 10, 2008, the total amount of water in storage (reservoir and ASR wellfields combined) was approximately 542 million gallons, or about seven percent (7%) of the Authoritys total storage capacity and less than one-third of the amount of storage at this time last year. On that same date, only 56 million gallons remained in the ASR wellfields, compared to a storage capacity of approximately 7.4 billion gallons.
The District has taken other emergency actions to assist the Authority during the current drought. Last month the District authorized the Englewood Water District to help the Authority by providing water to Charlotte County Utilities. This is allowing the Authority to reduce the amount of water it supplies to the county, which helps to extend its regional water supplies.
Additionally, in August 2007, the District authorized the Authority to pump additional water from the Peace River, when sufficient flows were available, to store in its reservoir and two ASR wellfields to help protect the drinking water supply. This emergency authorization remains in effect.
Since its issuance, the August 2007 order has allowed the withdrawal of approximately 1.3 billion gallons of water more than would have been normally authorized by the Authority’s permit. However, the prospect of additional withdrawals has diminished due to seasonal and drought-related declines in river flow.
During the past twelve months (February 2007 through January 2008) the southern basin of the Peace River received only 38.25 inches, compared to a typical historical value of 52 inches, resulting in a rainfall deficit of 13.75 inches. During the same period, the lack of rain in the northern basin of the Peace River has resulted a rainfall deficit of 14.07 inches. As a result of below normal of below normal rainfall in the Peace River watershed, the Peace Rivers stream flow is well below normal and the area is expected to continue to receive below normal rainfall through May.
The U.S. Drought Monitor has designated the Authoritys entire service area as experiencing “D2” or Severe Drought conditions as of February 26, 2008. The U.S. Drought Monitor has been detecting drought or drought-like conditions in this area for several months.
The combination of current hydrologic conditions and resulting water supply conditions constitute an ongoing threat to public water supplies and the public’s health, safety and welfare.