The Grand River Dam Authority’s (GRDA) annual “Rush for Brush” program is designed to rehabilitate aging lakes associated with its two hydro projects in northeastern Oklahoma. This program encourages local individuals to volunteer as partners in conservation by helping GRDA staff construct and deploy artificial structures (also known as spider blocks) to enhance fishery habitat throughout two Oklahoma lakes. Grand Lake O’ the Cherokees (commonly known as Grand Lake) is formed by Pensacola Dam, which was completed in 1940. The dam also impounds water for a 120-MW hydro station. Lake Hudson is formed by Robert S. Kerr Dam, completed in 1964, along with a 108-MW hydro plant. The goal of the Rush for Brush program, spearheaded by GRDA’s Office of Ecosystems Management, is to improve habitat for popular game fish in these two lakes.
The need for fish habitat
Grand Lake and Lake Hudson are home to many species of game fish, including crappie, bluegill, sunfish, bass, catfish, and spoonbill (or paddlefish). Over time, fish habitat in the form of old stumps and trees that were buried when the reservoirs were impounded began to rot and decay away. To address this phenomenon, fishermen have cut trees and limbs along the shoreline and sunk the materials in the lake. These brush piles attract adult fish and also serve as vital brood rearing habitat for fry and fingerlings. These structures have been used by fishery managers as a management tool for many years. However, this practice can have a detrimental effect on the shoreline of the lake. For example, frequent tree cutting and removal along the shoreline encourages soil erosion and reduces shoreline habitat used by other species of wildlife.
Local volunteers work with a representative of the Grand River Dam Authority to build spider blocks, a type of artificial fish habitat made of cinder blocks and PVC pipe.
Instead, GRDA’s Office of Ecosystems Management began using artificial structures (spider blocks) to simulate natural brush piles. These artificial structures provide protection to fry and fingerlings and will stay in place and last much longer than natural brush piles. The spider blocks are made with polyvinyl chloride (PVC) pipes embedded in concrete poured into each hole in a cinder block. The block anchors the structure to the bottom of the lake, and the pipes provide cover for and attract fish.
Taking the program public
To promote conservation and restoration, GRDA decided to solicit public participation in the Rush for Brush program. This program gives GRDA a means to educate fishermen and conservationists about sound management practices and shoreline conservation.
The first annual Rush for Brush event was held May 11-12, 2007, at Snowdale State Park on Lake Hudson. At that time, GRDA was the only organization requesting public assistance for the construction and deployment of spider blocks as artificial habitat in Oklahoma’s lakes. Thus, GRDA had no idea how many volunteers, if any, to expect at each event. GRDA turned to newspaper articles and promotions on the company’s website to publicize the first event and sought additional help from the GRDA lake patrol and power line right-of-way crews. These two departments helped contribute to the success of these events by delivering the materials to the construction sites.
Spider blocks – designed to provide habitat for fish – are lowered into Grand Lake in Oklahoma by local volunteers who participated in the Grand River Dam Authority’s annual “Rush for Brush” program.
That first year, GRDA held four Rush for Brush events – two events at Lake Hudson in May and two at Grand Lake in June. The overall goal was to build and place 500 spider blocks in the two lakes. At the first event in 2007, eight volunteers made 95 spider blocks. By the fourth event, June 8-9, 2007, more than 50 volunteers participated and GRDA ran out of materials. That year, 800 spider blocks were placed in the lakes. GRDA credits word of mouth among fishermen for pushing the program to such a high level of participation.
In 2008, more than 50 volunteers pre-registered for the first event in April at Grand Lake. Those volunteers helped build about 570 structures.
The spider blocks are simple to make. Cinder blocks are placed on plastic sheeting, about 4 feet apart. Concrete is poured into the cinder block holes and PVC pipe, cut into 4- to 6-foot lengths and frayed at one end, is inserted into the concrete. The frayed ends keep the pipe securely anchored in place. The blocks are allowed to dry for at least 24 hours. The cost per block is about $4.
On the second day of the Rush for Brush event, volunteers who helped fabricate the spider blocks pick up their blocks for deployment in their favorite fishing spots. Volunteers use placement strategies provided by GRDA personnel. To be most effective, GRDA recommends the spider blocks be placed in 12 to 20 feet of water, with no less than five structures placed within a 100 square foot area.
GRDA’s policy to allow volunteer fishermen to place spider blocks at their favorite fishing holes helps reduce fishing pressure over these structures, as their locations remain relatively unknown to the general public. Unlike marked public fishing areas that are fished on a regular basis, these areas receive less pressure and subsequently can provide a refuge for many species of fish.
GRDA receives a great deal of positive feedback from area residents regarding the Rush for Brush events. This program is expected to enhance lake habitat and the fishing experience for the average fisherman. More fish equals more fishermen, and more fishermen can only help stimulate the local economy as they shop for gas, food, and fishing supplies. The Rush for Brush event was featured in all of the local newspapers and on the evening news in Tulsa, Okla. The program has been featured in a few out-of-state publications.
GRDA is using a creel survey to measure the quantitative success of this program. Most recreational fisheries managers use a creel survey to quantify the number and species of fish landings in their lakes and waterways. The survey technique uses interviews with fishermen and a sampling program to estimate anglers’ catch and/or harvest. Results are expected in early 2009. However, in casual interviews, many local fisherman have indicated they are catching more fish over artificial blocks than over natural habitat or brush piles.
Lessons learned and future plans
The Rush for Brush program has helped raise the profile of GRDA in the lake communities. Community members now see GRDA as much more than just an electric company. The Office of Ecosystems Management plans to hold its Rush for Brush event each spring. To