LOWELL -- A series of ponds being built along Interstate 49 near Lowell aren't for fishing but rather to protect the blind Ozark cave fish and other sensitive, threatened or endangered creatures living in the Cave Springs recharge area, according to state highway officials.
The basins were developed through consultation with the U.S. Fish and Wildlife Service during an Endangered Species Act consultation process for the I-49 widening project, according to Josh Seagraves, section head over special studies with the Arkansas Highway and Transportation Department. They were also recommended in a later study looking at ways to protect the Cave Springs recharge area.
"A total of seven basins are to be constructed within the portion of the project which lies within the Cave Springs recharge area," according to Seagraves. "The I-49 corridor is outside of the direct recharge area for Cave Springs but is within the indirect recharge area."
The Ozark cave fish is a threatened vertebrate inhabiting caves in Arkansas, Oklahoma and Missouri. The highest number of cave fish live in Cave Springs cave, according to Mike Slay, Ozark Karst Program director for The Nature Conservancy of Arkansas. Slay is regarded by peers as one of the foremost experts on cave fish.
Cave fish and cave crawfish are considered indicator species for water quality, a "canary in the coal mine" as it were, because they have to have clean water to survive. Cave fish evolved over time to live in dark conditions, losing both their pigment and eyes, Slay said.
"On March 19, 2015, after a review of the [I-49 widening] project including the stormwater detention basin design, the USFWS concurred that the project 'may affect, but is not likely to adversely affect, listed species,'" according to Seagraves.
The Northwest Arkansas Regional Planning Commission later hired Crafton, Tull and Associates to partner with Ozark Underground Laboratory and Wright Water Engineers to study and fill in gaps of missing information from previous studies on the direct and indirect Cave Springs recharge area.
Crafton, Tull and Associates developed the design criteria including the size and locations of the ponds, according to Seagraves.
The Cave Springs recharge area is more than 12,500 acres where Cave Springs, Lowell, Springdale and Rogers come together. The ground underneath is porous karst, which allows water to flow through and form the Cave Springs spring. Developers haven't built much in the area largely because of concerns about harming the cave fish habitat, but the recharge area contains a lot of prime real estate for westward expansion of the metropolitan area.
The four cities have adopted regulations aimed at protecting the recharge area while allowing the area to develop.
"In karst settings, groundwater is very sensitive to what's going on on the surface," said Tom Aley with Ozark Underground Engineers. "Once contaminated water gets in the springs, we can't do much about it. The only way to effectively take care of groundwater is to protect the water quality on the surface."
Springs are underwater streams that work like a pipe, allowing water to move from one place to another and occasionally rise to the surface. Water goes in one place and comes out in another. Surface water going in -- runoff from rainfall for example -- needs to be filtered by plants and soil so the underground spring doesn't get contaminated.
The recharge area is broken into an indirect area of about 10.6 square miles, or 6,813 acres, and a more critical direct recharge area of about 8.9 square miles, or 5,702 acres. A lot of the direct recharge area immediately around Cave Springs is either developed with residential subdivisions or cannot be developed because of floodplains and steep terrain.
The most critical portion of the direct recharge area is about 1.8 square miles, or 1,167 acres, near the Cave Springs cave where geologic features allow water to go directly into the springs.
The study comes with some recommendations, including the use of buffer areas along sensitive streams and features such as the runoff detention ponds along Interstate 49 and Arkansas 264, piping sewage out of the area and best management practices for development.
Metro on 02/06/2017