Cedar Creek Reservoir Research Articles

Revision of the unusual Carboniferous ophiuroidCholaster(Echinodermata) and remarks on skeletal differentiation within the Asterozoa

AbstractNewly discovered, relatively well-preserved specimens ofCholaster whitein. sp. (Ophiuroidea, Echinodermata) are described from a small area of extensive outcrop of the Bangor Limestone (Mississippian, Chesterian) exposed on the edge of Cedar Creek Reservoir in northern Alabama, USA. The only other known species of the genus,C.peculiarisWorthen and Miller, is based on a single specimen exposed in dorsal aspect and collected from strata of similar age from southwestern Illinois. Incomplete preservation of the singleC.peculiarisspecimen limits comparisons, but differences between the two occurrences support separation at the species level.Skeletal remains of both asteroids and ophiuroids are first recognized from Early Ordovician sediments, and representatives of the two classes have retained plesiomorphies or converged morphologically since that time, thereby suggesting important evolutionary potentials and limitations.Cholasteris asteroid-like and unusual among ophiuroids in that the arms are comparatively broad and strap-like, and lateral ossicles are similar to asteroid adambulacrals and marginals, whereas the “vertebrae” (i.e., fused axial pair) and oral frame configurations ofC. whitein. sp. are typical of the Ophiuroidea. The oral frame ofC. peculiarisis unknown.A poorly preserved specimen of the asteroidDelicaster? also was recovered from nearby strata associated with theC. whitein. sp.UUID:http://zoobank.org/e0eea445-58e5-4096-80c1-a65964832ef6

Evaluation and Spatially Distributed Analyses of Proposed Cost-Effective BMPs for Reducing Phosphorous Level in Cedar Creek Reservoir, Texas

The assessment of BMP (best management practice) impacts using a watershed model has helped to establish a watershed conservation and protection plan that is projected to be required by government and decision makers. Cedar Creek watershed, located southeast of Dallas, Texas, was included in the 303(d) list as an impaired watershed due to high pH values. A number of efforts have been made to develop watershed protection plans by the North Central Texas Water Quality (NCTXWQ) project team. Tarrant Region Water District (TRWD) has monitored the water quality in the reservoir and found that chlorophyll-a has been increasing at an annual rate of 3.85%. Chlorophyll-a is a good indicator of algae growth, and TRWD, with 18 years of monitoring, revealed that the increase of chlorophyll-a needs to be a primary focus of the watershed protection plan. A stakeholder group and the project team suggested that total phosphorous (TP) reduction from the watershed should be targeted at 35% of current loading in order to preserve the water quality in the reservoir. In previous studies, flow and nutrients in the watershed were calibrated using SWAT (Soil and Water Assessment Tool). In addition, sensitivity analyses for each BMP were conducted such that each BMP was simulated in the model at a 100% adoption rate. The cost-effectiveness of each BMP was estimated and ranked by TP reduction. In this study, using the calibrated model and the cost-effectiveness analyses of the BMPs, the initially selected BMPs were simulated in SWAT to identify the reduction rate at the watershed outlet (reservoir) using a marginal adoption rate and to illustrate the spatially distributed impacts of each BMP at the subbasin scale. The results show that simulation of the eight selected BMPs in subbasins with higher TP loading can achieve the 35% reduction goal at the reservoir.

A Comprehensive Modeling Approach for Reservoir Water Quality Assessment and Management Due to Point and Nonpoint Source Pollution

A comprehensive modeling approach has been developed for use in formulating a watershed management plan to improve the water quality of Cedar Creek reservoir, one of five large water supply reservoirs in north central Texas operated by Tarrant Regional Water District. Eutrophication, or specifically the increase in concentrations of chlorophyll-a (chl'a') over the last 18 years, is a major concern for the water managers. To develop a watershed management plan, the watershed model SWAT was linked with the lake eutrophication model WASP. Several intensive field campaigns and surveys were conducted to collect extensive water quality and land management data for model setup and calibration. In addition to the streamflow, the SWAT model was well calibrated for sediment (including channel erosion) and nutrients. Further, a simple modification to the SWAT in-stream routine allowed simulation of the nutrient load due to channel erosion. The in-stream water quality parameters for SWAT were based on an independent QUAL-2E model calibration. The calibrated SWAT model showed that more than 85% of the total N and total P loading to the lake are from watershed nonpoint sources. Although cropland occupies only 6% of the watershed area, it contributed more than 43% of the sediment, 23% of total N, and 42% of total P loading from the watershed. The channel erosion contributed about 35% of the total sediment load. The watershed model identified subbasins that contribute considerable amounts of sediment and nutrients. Based on these loads, the calibrated WASP model showed that the watershed nonpoint-source nutrient load (total N and total P) should be reduced by at least 35% to see a significant reduction in chl'a' concentrations when compared to the WASP calibration levels.

Development and application of a WASP model on a large Texas reservoir to assess eutrophication control

Ernst, M.R. and J. Owens. 2009. Development and application of aWASP model on a large Texas reservoir to assess eutrophication control. The Tarrant Regional Water District developed and calibrated an 11-yr WASP-Eutro model for Cedar Creek Reservoir, a 13,350 ha (33,000 ac) drinking water supply and recreation reservoir located near Fort Worth, Texas, that is experiencing eutrophication. Cedar Creek was partitioned into 22 segments with up to three vertical segments in the main pool. Loading to the reservoir was divided into four categories: (1) watershed, (2) nine wastewater treatment plants (5.6 mgd), (3) atmospheric loading, and (4) internal NH4 and OPO4 sediment flux. Watershed loading was derived from a SWAT model of the 1007 mi2 watershed. Wastewater treatment plant loading was based on 1 yr of weekly plant nutrient and flow data. Atmospheric loading was estimated from periodic rain sampling adjacent to the reservoir. Internal flux was estimated from hypolimnetic accumulation during stratification. Calibration was judged by conformity of median observed and predicted water quality data and longitudinal profiles in the reservoir. Sensitivity analysis of these four loadings revealed that Chla and total phosphorus were most influenced by the watershed nonpoint source load. Internal flux was the next most influential load; form, timing and location of loading are more important than actual magnitude of this load. Estimates of the nonpoint source reduction necessary for a significant reduction in Chla were about 30%, while estimates of reductions in OPO4 flux to significantly reduce Chla were 75–100%. A combination of watershed and internal nutrient control are needed to control eutrophication in Cedar Creek Reservoir.

An Approach to Evaluating TMDLs to Support Permitted Discharges, Regulatory Agencies, and other Stakeholders

An Approach to Evaluating TMDLs to Support Permitted Discharges, Regulatory Agencies, and other StakeholdersIn November 2006 the South Carolina Department of Health and Environmental Control (SCDHEC) announced that a Watershed Analysis Risk Management Framework (WARMF) model application in the Catawba River Basin was available for public review. The model was developed by SCDHEC in response to impaired phosphorus conditions in Fishing Creek Reservoir, Cedar Creek Reservoir, and Lake Wateree which were...Author(s)Brian A. JacobsonTroy R. NaperalaBrooks M. SmithSourceProceedings of the Water Environment FederationSubjectSession 108: TMDLs: The Issues and the AnswersDocument typeConference PaperPublisherWater Environment FederationPrint publication date Jan, 2008ISSN1938-6478SICI1938-6478(20080101)2008:7L.7968;1-DOI10.2175/193864708788808834Volume / Issue2008 / 7Content sourceWEFTECFirst / last page(s)7968 - 7976Copyright2008Word count232

Coupling upland watershed and downstream waterbody hydrodynamic and water quality models (SWAT and CE-QUAL-W2) for better water resources management in complex river basins

Effective water resources management programs have always incorporated detailed analyses of hydrological and water quality processes in the upland watershed and downstream waterbody. We have integrated two powerful hydrological and water quality models (SWAT and CE-QUAL-W2) to simulate the combined processes of water quantity and quality both in the upland watershed and downstream waterbody. Whereas the SWAT model outputs water quality variables in its entirety, the CE-QUAL-W2 model requires inputs in various pools of organic matter contents. An intermediate program was developed to extract outputs from SWAT at required subbasin and reach outlets and converts them into acceptable CE-QUAL-W2 inputs. The CE-QUAL-W2 model was later calibrated for various hydrodynamic and water quality simulations in the Cedar Creek Reservoir, TX, USA. The results indicate that the two models are compatible and can be used to assess and manage water resources in complex watersheds comprised of upland watershed and downstream waterbodies.

Long-term Breeding Success of the Cattle Egret in Texas

A 28-year (1974-2002) study of the Cattle Egret (Bubulcus ibis) was conducted on Bird Island and Telfair Island at Cedar Creek Reservoir in northeast Texas to determine trends and dynamics of clutch/brood sizes, hatching success, chick mortality, and nest-site vegetation. For the breeding colonies on these islands, annual mean clutch size ranged from 2.71-3.73 (overall mean = 2.98) and from 2.56-4.18 (overall mean = 3.33); annual mean brood sizes ranged from 2.20-3.08 (overall mean = 2.60) and from 2.38-3.67 (overall mean = 2.87). Annual mean hatching success on the islands was high throughout the study (78%-94% [overall mean = 88%] and 71%-96% [overall mean = 86%]). Annual mean chick mortality was low (0.5%-13% [overall mean = 4.5%] and 0%-10% [overall mean = 2.1%]). Among marked broods on both islands, only 6.5% lost chicks, for which the mean loss was 1.16 chicks/brood. Generally, within these broods, there was higher mortality of the younger chicks. In broods of more than two chicks, the mortality ratio between 1st- and 2nd-hatched chicks was lower than other combinations of sibling rank. Decline of nest density coincided with the cumulative adverse effects of guanotrophication on nest-site vegetation. The original native nest-site vegetation was replaced by Chinaberry (Melia azedarach), an exotic tree that provided optimal nest sites until it too became intolerant to guanotrophy, which resulted in a continued decline in nest-site vegetation. During the time of declining availability of nest-site vegetation, the egrets began ground nesting; by 2002, 48% of nests were on the ground.

STREAM FLOW ESTIMATION USING SPATIALLY DISTRIBUTED RAINFALL IN THE TRINITY RIVER BASIN, TEXAS

Rainfall is the driving force behind all hydrologic processes in a watershed, and therefore the driving force in hydrologic modeling. In the past, raingauge data has been used as the primary input for these models. However, raingauge networks are generally sparse and insufficient to capture the spatial variability across large watersheds. A relatively new alternative is high-resolution radar rainfall data from weather radar systems, such as the Next Generation Weather Radar (NEXRAD) of the National Weather Service (NWS). In this study, raingauge data were compared to NEXRAD data at each raingauge location to evaluate the accuracy and validity of rainfall data measured by radar. The main objective of this study was to evaluate the use of spatially distributed rainfall on stream flow estimation using radar rainfall inputs to a hydrologic model. SWAT, a distributed-parameter continuous-time hydrologic/water quality model, was used to estimate stream flow for a watershed in the Trinity River Basin of northeast Texas. Results obtained from simulations using NEXRAD rainfall inputs were compared to those obtained using traditional raingauge data as input to the same model. Estimation efficiency analysis was used to compare the storage volume for the Cedar Creek Reservoir with daily, ten-day, and monthly accumulated flow from SWAT simulations using raingauge and NEXRAD rainfall inputs. The efficiency for both models was similar; however, NEXRAD rainfall inputs seem to provide a better flow estimate. The accuracy of the model results suggest that NEXRAD is a good alternative to raingauge data, and can be extremely valuable in large watersheds without readily available raingauge data or sparse raingauge networks. In addition, NEXRAD can capture rainfall from localized events that may be missed by raingauge networks but that still contribute to overland runoff, thus contributing to stream flow.