Introduction and Purpose
Problems Affecting Habitat and Species
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- Priority Research and Monitoring Efforts
- Cypress Creek Basin Associated Maps
- Associated Section IV Documents
- Location and Condition of Cypress Creek Basin
- Associated Water Bodies
- Problems Affecting Habitat and Species
- Guadalupe River Basin Associated Maps
- Location and Condition of Guadalupe River Basin
| Problems Affecting Habitat and Species
Riverine habitat on the Colorado River has been substantially modified as a result of the construction and operation of reservoirs. All of the major reservoirs within the basin are operated as water supplies; the Highland Lakes and Lake Austin also include hydropower operations. E. V. Spence and O. H. Ivy Reservoirs (CRMWD) have substantially modified flow regimes in the upper Colorado River; both are required to release water to maintain instream habitat for the Concho River water snake (Nerodia harteri), a federally threatened species. The Highland Lakes regulate flow in the lower 300 miles of the Colorado River, from Austin to Matagorda Bay. The LCRA has identified appropriate instream flows for the Colorado River (Mosier and Ray 1992) and those flows have been integrated into the LCRA’s management plan for the Highland Lakes and the lower Colorado River. The Colorado River and its tributaries support several threatened and endangered aquatic species. In addition to the Concho River water snake, the endangered Clear Creek gambusia (Gambusia heterochir), and Barton Springs salamander (Eurycea sosorum) are endemic to Clear Creek Springs in the San Saba watershed and the Barton Springs complex in Austin, respectively. The blue sucker (Cycleptus elongatus) which is found in the Colorado River downstream of Austin, is listed as threatened by the state of Texas. Hydropower operations are a significant issue in the Colorado River mainstem immediately downstream of Austin. All of the LCRA’s reservoirs (Buchanan, Inks, L.B.J., Marble Falls, and Travis) and Lake Austin are operated for hydropower generation conjunctively with water supply operations. Since the Highland Lakes chain, and Lake Austin form a continuous chain of impoundments with no intervening freeflowing reaches, the impact of hydropower operations on aquatic habitat is largely confined to the riverine reaches immediately downstream of Austin. The LCRA operates the reservoirs to meet peak electrical demand; consequently there are substantial daily fluctuations in water level immediately downstream of Austin. Kills have occurred in, and near, this river from the area near Colorado City downstream to the area of the city of Bend as a result of of toxic golden alga blooms. The golden alga (Prymnesium parvum) produces toxins that kill all fish species, mussel/clam species, and gill breathing amphibians/salamanders. It is a threat to all aquatic ecosystems. Research is needed on its distribution; bloom and toxin production dynamic; water quality affects on the alga and its toxin; possible management/treatment options for ponds and large waterbodies; interactions, population control, and affects within the plankton community (bacteria, phytoplankton, and zooplankton); and genetics of the organism and its possible stains. The need for coordination and cooperation between the various regulatory and resource agencies (local, state, and federal) is a very important need for developing research efforts and any future management plans or actions dealing with this toxic alga. Priority Research and Monitoring Efforts
Conservation Actions
Cypress Creek Basin Associated Maps Texas Rivers and River Basins…….............. 12 Sulphur River and Cypress Creek Basins….. 16 Minor Aquifers………………….…............. 26 Major Aquifers……………………………...27 Texas Rivers and Reservoirs……………...... 28 Associated Section IV Documents The Texas Priority Species List……………..743 Priority Species
Location and Condition of Cypress Creek Basin The Cypress Creek basin has its origins in northeast Texas and drains an area of 2,812 square miles (TWDB 1997). It is contained within the Post Oak Savannah and Pineywoods ecoregions (Gould 1960, BEG 1996). The landscape consists of rolling wooded hills and broad, frequently flooded, and densely vegetated stream bottoms. Big Cypress Creek’s extensive floodplain is marked by numerous sloughs, oxbows and other wetlands that trap water and sediment following flood events, forming important wetland habitat. Typical floodplains are heavily wooded with semi-aquatic species (e.g. bald cypress) and are undisturbed relative to uplands, which are extensively used for ranching. Land uses in the Cypress Creek basin include: woodlands (66%), agriculture (28%), urban (5.5%), and water (4.3%) (NETMWD 2000). Rainfall is abundant ranging from 35 inches per year at the western extreme of the basin to over 55 inches annually at the Louisiana border. Total storage capacity in the basin exceeds 790,000 acre-feet (TWDB, unpublished data). Black Cypress Bayou and Little Cypress Creek are the only major tributaries that are unimpounded. Caddo Lake was once one of the largest natural lakes in the South. Originally, it was impounded by a large log jam on the Red River, which was removed by the U.S. government in 1874 to facilitate navigation. In 1914 a dam was constructed near Mooringsport, Louisiana. The U.S. Army Corps of Engineers (USACE) completed a replacement dam in 1971. In 1993 Caddo Lake was recognized as an international wetlands site. The economy of the basin is comprised of manufacturing, retail and wholesale trade, mineral production and agriculture (TWDB 1997). Intensive poultry operations are located in the upper watersheds of the major watercourses. Major cities include Marshall, Mount Pleasant, Atlanta, and Gilbert. In 1990, the population of the basin was 124,177 (TWDB 1997). Water management in the basin is controlled by several districts, which own and operate the large reservoirs. The Red River Compact apportions waters of the Red River basin among Oklahoma, Arkansas, Louisiana and Texas. Surface water sources supply about 89% of the water demand. Three water body segments are listed as impaired on the 2004 draft 303(d) list (TCEQ 2005). Various areas of Caddo Lake are listed for different reasons, including depressed dissolved oxygen concentrations, mercury in largemouth bass and freshwater drum, and low pH. Big Cypress Creek below Lake O’ the Pines is listed for mercury in fish tissue, lead (chronic) in water, low pH, and depressed dissolved oxygen. Harrison Bayou is listed for depressed dissolved oxygen. Associated Water Bodies Cypress Creek contains two major tributaries, Black Cypress Bayou and Little Cypress Creek, which join Big Cypress Creek near the town of Jefferson before entering Caddo Lake. In Louisiana Black Bayou and James Bayou feed into Big Cypress Creek which joins the Red River near Shreveport, Louisiana. Large multi-purpose (flood control and water supply) reservoirs constructed on Big Cypress include Lake O’ the Pines and Bob Sandlin. The largest reservoir is Lake O’ the Pines. It was constructed by USACE to control flooding in Jefferson, Texas, which is located upstream of Caddo Lake. Northeast Texas Municipal Water District (NETMWD) controls releases when reservoir stage is below flood pool. There are nine smaller reservoirs in the watershed (excluding Caddo Lake); several of these provide cooling water for steam-electric power plants. Reservoirs
Aquifers Cypress Creek and its reservoirs are all found over the Carrizo-Wilcox Aquifer in northeast Texas. Therefore, groundwater supplies are largely obtained from the Carrizo-Wilcox Aquifer. Problems Affecting Habitat and Species Major reservoirs have altered the flow regime in the Cypress basin. Operations of Lake O’ the Pines have dramatically altered flow regimes downstream in Big Cypress Creek. Most notable is that pre-dam flows included peak flows exceeding 57,000 cfs while post-dam peak flows rarely exceed 3,000 cfs; variation in peak flows has been dramatically reduced. Low flows during the historically dry periods have noticeably increased following dam construction. Significant physical effects on riverine and floodplain habitat include: reduced floodplain connectivity, altered channel and habitat-forming processes, and altered sediment transport and deliver. Influences on biological processes, include reduced seed dispersal, encroachment of upland species into floodplains, alterations to spawning and foraging habitat and potential elimination of spawning cues for fishes. The paddlefish (Polyodon spathula) has been greatly reduced in abundance and distribution throughout its range including the Cypress basin. Paddlefish spawn in the spring when water levels rise rapidly. After the larvae develop within deep pools the juveniles move into backwater habitats. Spring floods have been greatly curtailed in Big Cypress Creek, and this may have eliminated cues and conditions needed for spawning. In addition, the lack of floods has likely resulted in the degradation of shoal habitats that are critical spawning habitat for this species. In the past, paddlefish were stocked in Caddo Lake in hopes to recover populations in the Cypress basin which were extirpated in the 1960’s. The bluehead shiner (Notropis hubbsi) is a state-threatened species that schools in backwaters and spawns from early May to July. It appears that late spring and early summer low flow conditions may be most conducive to successful spawning and recruitment, but its presence in oxbow lakes reveals a necessity for periodic overbank flows allowing dispersal between channel and oxbow habitats. Oil drilling and chicken farming are presumed to have negatively impacted mussel populations. Hydrologic modifications have not been the only negative impact to this system. Other perturbations, such as nutrient and contaminant loading, logging, and drainage and conversion of the watershed to agriculture or residential development, have altered the system. Growth of macrophytes in the upper reaches of Caddo Lake are problematic in that decay of this accumulated biomass leads to conditions of low dissolved oxygen. Exotic species such as hydrilla and water hyacinth are abundant. Caddo Lake also suffers from pollution of heavy metals and organic chemicals from multiple sources. In the past, this has even led to warnings to limit the consumption of large fish. No major water development projects that affect the Cypress basin were identified in the state water plan (TWDB 2002). Black Cypress and Little Cypress reservoirs have been proposed in past water plans; Little Cypress, on Little Cypress Creek, was recommended as a unique reservoir site (TWDB 2002). Potential hydropower issues could develop for Lake O’ the Pines. Priority Research and Monitoring Efforts
Conservation Actions
Guadalupe River Basin Associated Maps Texas Rivers and River Basins…………...... 12 Guadalupe and San Antonio River Basins…. 17 Minor Aquifers………………….…............. 26 Major Aquifers……………………………...27 Texas Rivers and Reservoirs………………..28 Associated Section IV Documents The Texas Priority Species List……………..743 Priority Species
Location and Condition of Guadalupe River Basin Rising from its North and South forks in Kerr County, the spring-fed river flows eastward into Kendall and Comal Counties where it then turns and flows south to the Gulf of Mexico, crossing Guadalupe, Gonzales, DeWitt, Victoria, Calhoun, and Refugio Counties along the way. Its total length is approximately 250 miles (Bureau of Economic Geology 1996a; Texas Natural Resource Conservation Commission 2000). Over its course, the river traverses the Edwards Plateau, Blackland Prairie, Post Oak Savannah, and Gulf Coast Prairies and Marshes physiographic ecoregions (Gould 1960, Bureau of Economic Geology 1996). Total basin drainage area is 6070 square miles and rainfall varies from 30 to 40 inches per year (Bureau of Economic Geology 1996). One major reservoir, Canyon Reservoir, and several smaller ones, Lake McQueeney, Lake Dunlap, Lake Placid, Lake Gonzales, Wood Lake, and Meadow Lake, are located on the river (U.S. Fish and Wildlife Service 1976). The upper reaches of the Guadalupe River meander through limestone bluffs and banks lined with a wide diversity of trees. Numerous rapids and falls exist which attract great numbers of water enthusiasts. The aquatic and riparian habitats support an exceptionally diverse assemblage of invertebrates, fish, birds, mammals, and plants characteristic of the Edwards Plateau (Kutac and Caran 1994). From Kendall County to Comal County the Guadalupe River is one of the most scenic stretches of river in Texas. Except during periods of extreme drought there is always sufficient water in this section of the river for recreational use. From Canyon Dam to Interstate Highway 35 the Guadalupe River in Comal County is considered one of the finest white-water stretches in the State. The river is scenic, with limestone bluffs, bald cypress (Taxodium distichum), pecan (Carya illinoensis), elm (Ulmus sp.), and other vegetation lining the banks. The river along this stretch is being subjected to development, with many subdivisions becoming evident; however, many natural areas can still be found. The flow of the river here is largely controlled by water releases from Canyon Dam. Gradient decreases in the middle reach as the river leaves the Edwards Plateau and runs toward the Gulf Coast Prairies and Marshes. As a result the river becomes slower moving. Water clarity also declines as substrates shift from limestone to much more erodable soil types (Belisle and Josselet 1974). The lower reach contains extensive freshwater and estuarine wetlands, including the Guadalupe Delta Wildlife Management Area, which is one of the largest wetland reserve projects in the United States at almost 6,000 acres (B. Ortega 1999, pers. comm.). Overall, the Guadalupe River Basin is characterized by generally high water quality throughout; however, seven water body segments are listed as impaired on the 2004 draft 303(d) list (Texas Commission on Environmental Quality 2004). All the listings are due to depressed dissolved oxygen and/or high bacteria counts. Low dissolved oxygen concentrations were found to be generally restricted to the tidal segment and to smaller tributaries. Elevated fecal coliform bacteria levels were found in four tributaries and in the mainsteam reach upstream of Canyon Reservoir. Associated Water Bodies Blanco River The Blanco River rises in northeast Kendall County, then flows approximately 87 miles southeast through Blanco and Hays Counties, where it joins the San Marcos River just downstream of the City of San Marcos. The upper reach consists of long, shallow stretches flowing over a limestone substrate. It is noted for historic Indian mounds, unusual geologic formations, and dinosaur tracks. Limestone bluffs and bald cypress line the banks. The middle and lower reaches of the Blanco River flow through some of the most interesting scenery in Central Texas. The river continues to flow over a bed of limestone and the banks are lined with bald cypress, pecan, black willow (Salix nigra), and sycamore (Platanus occidentalis) trees, while the hills away from the river are covered with oaks (Quercus sp.) and Ashe juniper (Juniperus ashei). Numerous outcroppings of rocks and bluffs are present. Two noteworthy landmarks are "the narrows" and "Devil's Backbone". The narrows is an area where the river is constricted between steep bluffs while the Devil's Backbone is an extensive area of rugged, hilly country located adjacent to the river. The river is extremely shallow for several miles downstream of Blanco, until sufficient spring and creek inflows increase the water level in the vicinity of the Devil's Backbone near Wimberley. Comal River The Comal River is one of two major tributaries to the Guadalupe River, the other being the San Marcos River. It rises from Comal Springs, within the City of New Braunfels, and has the distinction of being the shortest river in the state (only two and one-half miles long); however, its flow contribution is significant. Average discharge is 330 cfs and when combined with the San Marcos River contributes around 30 percent of the total annual flow recorded in the Guadalupe River (Espey 1988). During the drought of record (1948-1956) spring flow from these two rivers contributed on average 48 percent of the total annual flow at that same location (Espey 1988). San Marcos River The San Marcos River originates from Aquarena Springs (second largest spring in Texas, with Comal Springs being the largest) within the city limits of San Marcos. The springs have historically exhibited the greatest flow dependability and environmental stability of any spring system in the southwestern United States and as a consequence have a greater known diversity of aquatic organisms than any other ecosystem within that area (U.S. Fish and Wildlife Service 1984). The river flows about 75 miles through heavily wooded banks to join the Guadalupe River near Gonzales. Reservoirs
Aquifers The Guadalupe River Basin cuts across five major aquifers on its way to the Gulf of Mexico. These include the Edwards-Trinity, Trinity, Edwards, Carrizo-Wilcox, and Gulf Coast (Bureau of Economic Geology 2001). The river begins in the Edwards-Trinity Aquifer in Kerr County and flows southeast over the Trinity and Edwards Aquifers. Once across the Edwards Aquifer, the river moves through Guadalupe County over to the Carrizo-Wilcox Aquifer. Southeast of the Carrizo-Wilcox Aquifer, the Guadalupe River flows over the Gulf Coast Aquifer, a large aquifer lining the majority of the Texas coast. Problems Affecting Habitat and Species The population in the South Central Texas regional water planning area (Region L), which includes all but the uppermost reach of the Guadalupe River in Kerr County, is projected to double between 2000 and 2060, reaching more than four million people (Texas Water Development Board 2005). The Lower Guadalupe Water Supply Project has been approved for inclusion in the state water plan by Region L to provide an additional source of water to meet future needs in the region. Components of the project include diversion of water at a point on the Lower Guadalupe River downstream of the confluence of the San Antonio River as well as additional groundwater pumping primarily from the Gulf Cost Aquifer System (Lower Guadalupe Water Supply Project 2004). A number of technical and environmental studies have been initiated regarding the project. Major water right applications pending at TCEQ include a request for 289,600 acre-feet per year. Priority Research and Monitoring Efforts
Conservation Actions
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