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Conttibnled Paper - Young et al. - Phantom Lake Spnng Endangered Fish Refughan
<br />overhead cover for fish introduced into the refugium.
<br />Specimens of the Reeves County snail Cochliopa
<br />texana and diminutive amphipod Gammarus
<br />hyalelloides were captured within the refugium during
<br />fish introductions, indicating invertebrates had begun
<br />colonization of the newly created habitats.
<br />Because few C. elegans were collected in the
<br />Phantom Lake Springs area, the Recovery Team
<br />decided to introduce a stock of C. elegans that are
<br />currently held at Uvalde National Fish Hatchery.
<br />Personnel from TPWD were contacted to conduct
<br />genetic analysis of this hatchery stock. This study
<br />subsequently determined that the hatchery stock C.
<br />elegans were suitable for introduction. On October 14,
<br />1993, 109 C. elegans were introduced into various
<br />pools, utilizing the same methods as above. These fish
<br />have been observed utilizing faster velocity waters
<br />throughout the refugium. Numerous C. elegans have
<br />since been observed downstream in the main canal and
<br />perhaps migrated out of the refugium.
<br />A cooperative agreement was developed between
<br />Reclamation and Texas A&M University (TAMU) in
<br />fall, 1993, for aquatic monitoring studies. Under this
<br />agreement, researchers from TAMU will sample
<br />Phantom Lake Springs on a quarterly basis for two
<br />years, monitoring habitat condition, fish abundance and
<br />microhabitat use, and water quality. Results of these
<br />monitoring efforts will indicate the success of this
<br />project and help determine future operational
<br />guidelines.
<br />Restoration of altered aquatic habitat and associated
<br />species is often a complex, controversial issue,
<br />especially when water rights and deliveries to users are
<br />impacted. However, as this project has indicated,
<br />affording protection to aquatic species can be
<br />accomplished without significant reduction in water
<br />deliveries to downstream users. Reductions in water
<br />during delivery to irrigators generally occur in two
<br />ways, seepage and evaporation. Evaporation can be
<br />somewhat controlled via shading of water by riparian
<br />vegetation, creation of a narrowed channel and
<br />increasing velocity. Seepage can be controlled by
<br />installation of a membrane or clay liner or concrete
<br />channel. Phantom Lake Springs refugium designs
<br />incorporated all these water saving methods.
<br />Historically, the District had resisted major
<br />modifications to the existing water distribution system.
<br />However, after negotiations to explain the water-saving
<br />measures being proposed for the refugium, District
<br />membership has not objected to restoration activities at
<br />Phantom Lake Springs. Flexible membrane liners have
<br />wide application to aquatic habitat restoration projects,
<br />are fairly cost effective, and should be considered for
<br />future restoration activities. Membrane liners provide
<br />reliable containment and seepage control for
<br />conservation of water. In contrast, traditional liner
<br />materials, such as clay and concrete, are not as
<br />reliable, and concrete is expensive and difficult to
<br />install. Membranes are conducive to areas of potential
<br />differential settlement, whereas concrete or clay liners
<br />usually fail. Concrete and clay liners can lose much of
<br />their barrier properties in the long run due to the
<br />absence of elasticity, difficulties of proper compaction,
<br />weathering effects, and root growth.
<br />Membrane liners are composed of many different
<br />materials including hypalon, polyvinyl chloride (PVC),
<br />high and low density polyethylene (HDPE and LDPE),
<br />and recycled rubber (ethylene propylene diene
<br />monomer - EPDM), just to name a few. The
<br />composition of the membrane, and related
<br />manufacturing practices, determine strength, elasticity,
<br />durability, and chemical, microorganism and ultra
<br />violet resistance. In many cases the material can be
<br />manufactured to select colors and textures. Textured
<br />liners are usually more expensive, but allow better
<br />stability of surface materials on steeper slopes (smooth
<br />liners should not be used for steep slopes or cover
<br />materials may slump). The following is presented as a
<br />general guideline for 30 mil membrane liners:
<br />Material utilities Cost/ft'
<br />Hypalon Extremely durable, UV light resistant $1.00
<br />PVC Somewhat durable, decay resistant $0.35
<br />LDPE Smooth Flexible, durable, UV resistant $0.50
<br /> Textured Flexible, durable, UV resistant $0.60
<br />EPDM Short life, decay-prone, light sensitive $0.30
<br />Installation of a liner is relatively easy; with most
<br />materials, reliable seams can be achieved in the field,
<br />and various shapes and patterns can be achieved.
<br />Membranes can be covered with soil to allow
<br />vegetative growth to enhance slope stability and
<br />provide for erosion control.
<br />Costs for design and construction of the refitgium
<br />channel at Phantom Lake Springs were more expensive
<br />than anticipated. Much of the excessive cost can be
<br />attributed to government overhead and personnel costs,
<br />and extra cost required by law during government
<br />contracting. Remote worksite location, uniqueness of
<br />the work, including modification of existing concrete
<br />canal, and contract modifications also increased overall
<br />costs. However, it is hoped that overall benefits to the
<br />aquatic resource, especially provision of an additional
<br />refugium for C. elegans, G. nobilis, and associated
<br />invertebrates, outweigh monetary considerations.
<br />Literature
<br />Brune, G. 1981. Springs of Texas, Volume 1.
<br />Branch-Smith, Inc. Ft. Worth, TX.
<br />Charles, M.C. 1993 (draft). Archeological evaluation
<br />and testing, Site 41JD63, Phantom Lake Springs, Jeff
<br />Davis County, Texas. Contract Report
<br />8-CS-40-06920 for Bureau of Reclamation. Complete
<br />Archeological Service Associates, Cortez, CO.
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