Guadalupe River Basin Research Articles

Applying Floodplain Inundation Modeling to Estimate Suitable Spawning Habitat and Recruitment Success for Alligator Gar in the Guadalupe River, Texas

We developed a floodplain inundation model to extract specific flood extent and depth parameters and combined these with vegetation land cover and historic flow data to quantify spatial habitat suitability and temporal hydrologic metrics that support Alligator Gar Atractosteus spatula spawning within a 257 km segment of the lower Guadalupe River, Texas, USA. We modeled nine flows across a range of flood frequency recurrence intervals from 257 m3s−1 to ~4997 m3s−1 and estimated the availability of suitable spawning water depths (0.2 to 2 m) and lateral connectedness between the river and suitable floodplain landcover types. We estimated the ages via otoliths of 95 Alligator Gar collected in the reach to determine the year that they were recruited into the system. We analyzed a total of 30 Indicators of Hydrologic Alteration flow metrics to examine how the spatially derived suitable habitats related to the temporal aspects of flow occurrence during the spawning season for the period of flow record April–July (1935–2020) and to the years spanning the recruitment data of the Alligator Gar (1981–2010). A non-linear relationship existed between suitable spawning habitat area and the flow regime, with the most habitat availability corresponding to the 10–20-year flood recurrence interval frequency with peak flows of 2057–3108 m3s−1, respectively. The Alligator Gar recruitment data indicated that six years provided high recruitment, which correlated with peak flows of ~5-year frequency with an available spawning area of ~9000 Ha, moderate recruitment years related to peak flows with ~3-year frequency with an available spawning area of 6000 Ha, and low recruitment years where spawning was likely to occur at least every other year with at least 2500 Ha of available spawning area. The results of this model support the development of legislatively mandated environmental flow standards for the Guadalupe River Basin, inform field-based efforts for collecting empirical and observational data on the species’ reproduction, and provide spatial and temporal information for designing conservation strategies for Alligator Gar.

Texas Rangers, Ranchers, and Realtors: James Hughes Callahan and the Day Family in the Guadalupe River Basin. By Thomas O. McDonald

Texas Rangers, Ranchers, and Realtors: James Hughes Callahan and the Day Family in the Guadalupe River Basin. By Thomas O. McDonald

Streamflow components and climate change: Lessons learnt and energy implications after hydrological modeling experiences in catchments with a Mediterranean climate

Sustainable water management should consider climate change effects to ensure its future availability. Hydrological modeling is a supportive tool for this analysis, which has been used in this work to assess the climate change impacts on the water resources of three basins under Mediterranean climate (Ompólveda and Salado River basins, in Spain, and Guadalupe River basin, in Mexico).The outcomes of previous climate change scenarios simulation addressed with the Soil and Water Assessment Tool (SWAT) have been compiled, evaluating the impacts on the water balance, and focusing on the streamflow components. The potential implications of these effects on energy production have been discussed.The results point to a streamflow reduction by the end of the century around 50%–60% in the worst scenarios, with varying effects for each of the streamflow components. In the Spanish catchments, where groundwater contribution dominates in baseline conditions, a noticeable decrease of this component is expected (up to -74%), becoming lateral flow the main streamflow component. In the Mexican basin, lateral flow, which is already predominant (69%), will experience the largest absolute decrease, but the highest relative decrease might be experienced by groundwater flow, up to -92%. Absolute variations in the surface component are small and the different ways to simulate the climate change scenarios might hinder their interpretation.This work shows that water resources will be even more scarce in these regions, being especially worrying the groundwater component reduction, which currently maintains the streamflow during dry periods. This situation would limit energy production both from sources that directly use water, such as hydropower, and others that require water for cooling. Higher atmospheric and water temperatures will increase demands for irrigation and for cooling systems. Therefore, competition for water will rise among key sectors, and an accurate planning considering these factors must be a priority.

Texas Rangers, Ranchers, and Realtors: James Hughes Callahan and the Day Family in the Guadalupe River Basin by Thomas O. McDonald

Texas Rangers, Ranchers, and Realtors: James Hughes Callahan and the Day Family in the Guadalupe River Basin by Thomas O. McDonald

Texas Rangers, Ranchers, and Realtors: James Hughes Callahan and the Day Family in the Guadalupe River Basin by Thomas O. McDonald

Texas Rangers, Ranchers, and Realtors: James Hughes Callahan and the Day Family in the Guadalupe River Basin by Thomas O. McDonald

Development of a stochastic hydrological modeling system for improving ensemble streamflow prediction

Streamflow prediction plays a crucial role in water resources systems planning and the mitigation of hydrological extremes such as floods and droughts. Since a variety of uncertainties exist in streamflow prediction, it is necessary to enhance our efforts to robustly address uncertainties and their interactions for improving the reliability of streamflow prediction. This paper presents a stochastic hydrological modeling system (SHMS) for improving daily streamflow prediction by explicitly addressing uncertainties in error and model parameters as well as in forcing data and model outputs. Specifically, the SHMS merges the strengths of the ensemble Kalman filter and the particle filter algorithms for improving the effectiveness and robustness of daily streamflow assimilation. Factorial analysis of variance and variance-based global sensitivity analysis are performed to reveal parameter interactions affecting predictive performance and temporal dynamics of parameter sensitivities, maximizing the accuracy of streamflow prediction. The SHMS has been applied to the Guadalupe River basin located in Texas of the United States to demonstrate feasibility and applicability. Our findings indicate that the SHMS improves upon the well-known ensemble Kalman filter for sequential estimation of hydrological model parameters through a more rapid and accurate convergence of model parameters in streamflow simulation. The SHMS also demonstrates a higher level of skill in streamflow prediction compared to the conditional vine copula model. The proposed SHMS can be applied straightforwardly to other river basins for probabilistic hydrological prediction.

Service-Driven Modeling Approach to Managing Water Allocation in Priority Doctrine Regions

This work focuses on developing methods to better manage significant imbalances between water supply and demand during droughts. A service-driven approach (Model as a Service, or MaaS) is used to couple river modeling services with optimization services for determining optimal water allocation strategies under daily drought scenarios. It demonstrates the promise of coupling simulation-optimization model services to improve real-time water management in a service driven framework, which should be beneficial to many other water resource applications. The approach is implemented using the DataWolf workflow tool and AzureML Cloud machine learning services and applied to an April 2015 drought event in the Upper Guadalupe River Basin, Texas. Weather and water demand uncertainty are considered through scenario-based optimization. The optimization objective is to minimize the daily total curtailment hours across all groups of permit holders. The scenario analysis shows that the current permit grouping system has a significant impact on the optimal water allocation strategy. The scenarios also demonstrate that noncompliance of junior water users is predicted to have a much greater effect on the river system than noncompliance of senior water users. The resulting framework can be deployed for water allocation in any area by updating water user information, water allocation policy constraints, and river data that can be obtained from publicly available sources.

Occurrence of Golden Topminnow, Fundulus chrysotus, in the San Marcos River, Texas

Within the western extent of its range, Fundulus chrysotus (Golden Topminnow) is generally restricted to coastal drainages of Texas, with few reported occurrences inland. We report a new record of Golden Topminnow in the upper San Marcos River of Texas. The occurrence of Golden Topminnow could represent a natural range expansion or incidental introduction to the area. Future monitoring of the population within the San Marcos River (Guadalupe River basin) is needed to confirm if the species becomes established.

Probabilistic Projections of Multidimensional Flood Risks at a Convection‐Permitting Scale

AbstractUnderstanding future river flood risk is a prerequisite for developing climate change adaptation strategies and enhancing disaster resilience. Previous flood risk assessments can barely take into account future changes of fine‐scale hydroclimatic characteristics and hardly quantify multivariate interactions among flood variables, thereby resulting in an unreliable assessment of flood risk. In this study, for the first time, we develop probabilistic projections of multidimensional river flood risks at a convection‐permitting scale through the Weather Research and Forecasting (WRF) climate simulations with 4‐km horizontal grid spacing. Vine copula has been widely used to assess the multidimensional dependence structure of hydroclimate variables, but the commonly used frequentist approach may fail to identify the correct vine model and to obtain the uncertainty interval. Thus, a Bayesian vine copula approach is proposed to explicitly address the multidimensional dependence of flood characteristics (i.e., flood peak, volume, and duration) and underlying uncertainties. The proposed approach enables a robust assessment of return periods of future floods for Guadalupe and Mission river basins located in South Texas of the United States. Our findings reveal that the South Texas region is projected to experience more flood events with longer duration and greater discharge volume. The flood peak, however, will not necessarily increase even though precipitation extremes are expected to become more frequent. The projected flood return periods over the Guadalupe river basin do not show an obvious increase while the Mission river basin is projected to face a dramatic increase in flood risk with exposed to 100‐year and even severer floods nearly every 2 years, on average, when considering the combined effects of flood peak, volume, and duration.

Probabilistic Projections of Hydrological Droughts Through Convection‐Permitting Climate Simulations and Multimodel Hydrological Predictions

AbstractThe reliable projection of future changes in hydrological drought characteristics plays a crucial role in providing meaningful insights into agricultural development and water resources planning under climate change. In this study, we develop probabilistic projections of hydrological drought characteristics through a convection‐permitting climate simulation and a multimodel hydrological prediction for two major river basins in South Texas of the United States. The probabilistic hydrological drought projection depicts the future evolution of spatiotemporal characteristics of droughts under best‐ and worst‐case scenarios. Our findings reveal that there is a considerable variation in hydrological drought regimes near the urban area in South Texas. And the prolonged severe drought events are expected to be punctuated by the increasing extreme precipitation in a changing climate. This could lead to an increasing number of the dry‐wet abrupt alternation events. Moreover, hydrological droughts are projected to occur more frequently for the fall season in the Guadalupe River Basin and for the winter season in the Blanco River Basin, advancing our understanding of future changes in seasonal characteristics of hydrological droughts at a river basin scale.

Supply and Demand Analysis of Water Resources. Case Study: Irrigation Water Demand in a Semi-Arid Zone in Mexico

To sustainably use water resources, it is important to quantify water availability in a certain region. Due to climate change, population increase, and economic development, water demand increases continuously. Consequently, the difference between supply and demand of water becomes a significant issue, especially in arid and semi-arid regions. In this research, the Soil and Water Assessment Tool (SWAT) model has been applied to the Guadalupe river basin, to assess supply and demand analysis of water resources in this area, specifically for the irrigation of agricultural crops and municipal uses. From the land use, soil type, and terrain slope maps, 763 Hydrostatic Release Units (HRU) were estimated, distributed in the diverse relief types making up the basin, featured by mountains, hills, plateaus, plains, and valleys. For the crop area, 159 HRU were found with the three slope classification types, where 57 HRU represent 91% of the cultivated area on slopes, from 0 to 15%, located in the Ojos Negros and Guadalupe Valleys. The Soil Conservation Service method (SCS) was used to estimate the average monthly runoff and soil moisture content. As a result, water resource parameters related to the supply were determined with this, e.g., runoff, aquifer recharge, flow, infiltration, and others. Crop coefficient values (Kc) were used to determine crop evapotranspiration (ETc), to estimate the water demand of these for each month, using the multi-year monthly average reference evapotranspiration (ETo) calculated with the SWAT model. Overall good performance was obtained considering average monthly discharges data from the Agua Caliente gauging station. The model was calibrated, modifying the parameters chosen according to sensitivity analysis: SCS curve number, base-flow factor, ground-flow delay, and the threshold for return-flow occurrence. The Soil and Water Assessment Tool–Calibration and Uncertainty Programs SWAT-CUP has different goodness-of-fit indicators for the model e.g., determination coefficient (R2), standard deviation of the measured data (RSR), Nash–Sutcliffe coefficient of efficiency (NSE), and others. Multiple iterations were performed, resulting in a ratio between the root mean square error and the standard deviation of the measured data (RSR) of 0.61, a coefficient of determination (R2) of 0.70, and a Nash–Sutcliffe efficiency coefficient (NSE) of 0.63. A supply–demand analysis of the volume generated by the runoff from the basin was performed using the method of estimating useful volume for a reservoir. It is observed in these results that only positive deviations were obtained, implying that runoff in this basin is not enough to meet monthly demand. Finally, the need to establish actions to ensure water management efficiency is highlighted, both for irrigation of agricultural crops and for supply to the region population.

Quantifying the effects of urbanization on floods in a changing environment to promote water security — A case study of two adjacent basins in Texas

The increased occurrence of flood events resulting from urbanization and global climate change is a great threat to water security. To systematically evaluate the impacts of urbanization on floods, we applied a paired catchments approach to two adjacent river basins in south-central Texas — the San Antonio River Basin (SARB), with fast urbanization; and the Guadalupe River Basin (GRB), with little land cover change. A physics-based distributed hydrological model — the Distributed Hydrology Soil Vegetation Model, embedded with a multi-purpose reservoir module (DHSVM-Res) — was used to simulate streamflow and reservoir storage. The simulations were conducted under different land cover scenarios, including a newly developed continuous land cover series (CLCS). Holistic analyses were then conducted for the paired basins using three methods: analyzing the selected flood events, detecting change points (CP) of monthly floods, and testing the elasticity of long-term flood regimes. The results suggest that: (1) urbanization may reduce lag time and elevate flood peaks significantly by 3–30% in our study area; (2) when there is little land cover change, changing climate is the major driver of variations in the monthly maximum streamflow (MMS); (3) fast urbanization can amplify streamflow variability, increase MMS significantly, and thus alter the timing of CP; and (4) the mean MMS of observed streamflow in the SARB has increased by as much as 75.7% from the pre-CP to post-CP periods. This comprehensive study fills in a gap in our current understanding of the isolated impacts of urbanization on flooding and is expected to support future explorations of anthropogenic influences on floods.

A comprehensive approach uncovers hidden diversity in freshwater mussels (Bivalvia: Unionidae) with the description of a novel species.

Major geological processes have shaped biogeographical patterns of riverine biota. The Edwards Plateau of central Texas, USA, exhibits unique aquatic communities and endemism, including several species of freshwater mussels. Lampsilis bracteata (Gould, 1855) is endemic to the Edwards Plateau region; however, its phylogenetic relationship with other species in the Gulf coastal rivers and Mississippi River basin is unknown. We evaluated phylogenetic relationships, shell morphologies and soft anatomy characters of L.bracteata and a closely related congener, Lampsilis hydiana (Lea, 1838) throughout their ranges. Our results showed the presence of an undescribed species: Lampsilis bergmanni sp.n. Lampsilis bracteata and L.bergmanni sp.n. share similar shell morphologies and soft anatomy characters; however, they are genetically distinct. Geological processes, such as faulting and sea-level changes during the Miocene to Pliocene, are likely to have facilitated diversification of Lampsilis species, resulting in isolation of L.bracteata on the Edwards Plateau and diversification between L.bergmanni sp.n. and L.hydiana. We conclude that L.bracteata range is restricted to the Colorado River basin, whereas L.bergmanni sp.n. occurs only in upstream reaches of the Guadalupe River basin. Conservation actions are warranted for both species due to their restricted distributions and potential anthropogenic threats.

Improving probabilistic hydroclimatic projections through high-resolution convection-permitting climate modeling and Markov chain Monte Carlo simulations

Understanding future changes in hydroclimatic variables plays a crucial role in improving resilience and adaptation to extreme weather events such as floods and droughts. In this study, we develop high-resolution climate projections over Texas by using the convection-permitting Weather Research and Forecasting (WRF) model with 4 km horizontal grid spacing, and then produce the Markov chain Monte Carlo (MCMC)-based hydrologic forecasts in the Guadalupe River basin which is the primary concern of the Texas Water Development Board and the Guadalupe-Blanco River Authority. The Parameter-elevation Regressions on Independent Slopes Model (PRISM) dataset is used to verify the WRF climate simulations. The Model Parameter Estimation Experiment (MOPEX) dataset is used to validate probabilistic hydrologic predictions. Projected changes in precipitation, potential evapotranspiration (PET) and streamflow at different temporal scales are examined by dynamically downscaling climate projections derived from 15 Coupled Model Intercomparison Project Phase 5 (CMIP5) general circulation models (GCMs). Our findings reveal that the Upper Coast Climate Division of Texas is projected to experience the most remarkable wetting caused by precipitation and PET changes, whereas the most significant drying is expected to occur for the North Central Texas Climate Division. The dry Guadalupe River basin is projected to become drier with a substantial increase in future drought risks, especially for the summer season. And the extreme precipitation events are projected to increase in frequency and intensity with a reduction in overall precipitation frequency, which may result in more frequent occurrences of flash floods and drought episodes in the Guadalupe River basin.

Distinctive macroinvertebrate communities in a subtropical river network

Macroinvertebrates are widely used as bio-indicators in streams and rivers, and it is usually assumed that their community composition is primarily controlled by local environmental conditions. We examined the distribution of macroinvertebrates within the Guadalupe River basin (3256 km2) in Central Texas across physiographic gradients. Spatial analysis with variables that considers flow direction, connectivity and distances between sites (asymmetric eigenvector maps, AEM) detected distinctive communities in the lower reaches of the mainstem, in spring-influenced reaches, and in a tributary with intermittent reaches. Variation partitioning with redundancy analysis showed that large-scale factors, i.e. riverine network patterns (large-scale AEM variables), climatic variation and ecoregion explained a significant proportion (28%) of the variation in community composition within a river basin. The riverine network patterns were the most important factor, explaining 12% alone. Local environmental factors were significant, but completely confounded within these spatial patterns. We propose that there are distinctive macroinvertebrate communities depending on the location in the river network and this may apply to other (subtropical) rivers, which should be tested by future studies. We recommend spatial analysis that considers distances and connectivity within a river network as a powerful tool to recognize multiscale riverine network patterns, which can help to identify priority areas for conservation and to develop sound monitoring programs.

Improving Robustness of Hydrologic Ensemble Predictions Through Probabilistic Pre‐ and Post‐Processing in Sequential Data Assimilation

AbstractData assimilation using the ensemble Kalman filter (EnKF) has been increasingly recognized as a promising tool for probabilistic hydrologic predictions. However, little effort has been made to conduct the pre‐ and post‐processing of assimilation experiments, posing a significant challenge in achieving the best performance of hydrologic predictions. This paper presents a unified data assimilation framework for improving the robustness of hydrologic ensemble predictions. Statistical pre‐processing of assimilation experiments is conducted through the factorial design and analysis to identify the best EnKF settings with maximized performance. After the data assimilation operation, statistical post‐processing analysis is also performed through the factorial polynomial chaos expansion to efficiently address uncertainties in hydrologic predictions, as well as to explicitly reveal potential interactions among model parameters and their contributions to the predictive accuracy. In addition, the Gaussian anamorphosis is used to establish a seamless bridge between data assimilation and uncertainty quantification of hydrologic predictions. Both synthetic and real data assimilation experiments are carried out to demonstrate feasibility and applicability of the proposed methodology in the Guadalupe River basin, Texas. Results suggest that statistical pre‐ and post‐processing of data assimilation experiments provide meaningful insights into the dynamic behavior of hydrologic systems and enhance robustness of hydrologic ensemble predictions.

“Governance restricts”: A contextual assessment of the wastewater treatment policy in the Guadalupe River Basin, Mexico

Lack of wastewater treatment is among the main water problems worldwide. The implementation of wastewater treatment policies faces varying challenges given the many different contexts. Therefore, context-sensitive approaches are required from a governance perspective. This paper aims to improve the understanding of the role of contextual factors in water and wastewater governance drawing on empirical evidence from Latin America, with a focus on the Guadalupe River Basin in Mexico. The findings indicate that the governance context restricts the implementation of wastewater treatment policy. Thus, future reforms should consider the top-down nature of the policy implementation process.

Evaluating the impacts of farmers' behaviors on a hypothetical agricultural water market based on double auction

AbstractAgricultural water markets are considered effective instruments to mitigate the impacts of water scarcity and to increase crop production. However, previous studies have limited understanding of how farmers' behaviors affect the performance of water markets. This study develops an agent‐based model to explicitly incorporate farmers' behaviors, namely irrigation behavior (represented by farmers' sensitivity to soil water deficit ) and bidding behavior (represented by farmers' rent seeking and learning rate ), in a hypothetical water market based on a double auction. The model is applied to the Guadalupe River Basin in Texas to simulate a hypothetical agricultural water market under various hydrological conditions. It is found that the joint impacts of the behavioral parameters on the water market are strong and complex. In particular, among the three behavioral parameters, affects the water market potential and its impacts on the performance of the water market are significant under most scenarios. The impacts of or on the performance of the water market depend on the other two parameters. The water market could significantly increase crop production only when the following conditions are satisfied: (1) is small and (2) is small and/or is large. The first condition requires efficient irrigation scheduling, and the second requires well‐developed water market institutions that provide incentives to bid true valuation of water permits.

Genetic diversity and divergence in the fountain darter (Etheostoma fonticola): implications for conservation of an endangered species

The endangered fountain darter Etheostoma fonticola is found only in the Comal and San Marcos rivers in the Guadalupe River basin in central Texas, USA. Comal River fountain darters were believed to be extirpated following a severe drought in the 1950s and were reintroduced in the early 1970s using 457 darters from the San Marcos River. In this study we used 23 microsatellite loci to describe and evaluate the genetic diversity, population structure and effective population size (N e) of fountain darters. We also evaluated the genetic effect of the Comal River reintroduction and the influence of low-head dams (dams) on dispersal in both rivers. Bayesian analysis of individual genotypes and Analysis of Molecular Variation supported two distinct populations concordant with the two rivers. Estimates of N e were much smaller (<10 %) than census size (N c) in both rivers but did not indicate the populations are at risk of an immediate and rapid loss of genetic diversity. Coalescent-based estimates of the genetically effective number of founders (Nf) for the Comal River averaged about 49 darters and, together with the indices of genetic diversity and the bottleneck test (heterozygosity excess) results, were consistent with a founder event following the reintroduction in the Comal River. Finally, our results regarding the influence of dams on fountain darter dispersal were equivocal and did not support a conclusion. We recommend this issue be examined further as part of the fountain darter recovery program.

Hydrological modeling and climate change impacts in an agricultural semiarid region. Case study: Guadalupe River basin, Mexico

In northern Mexico, water resources management has become a challenging task, aggravated by the vulnerability of this region to climate change. The semiarid Guadalupe River Basin is under additional pressure due to wine production and drinking water supply. We have applied the SWAT model to the upper section of this basin to assess the impacts of several climate change scenarios on its water availability. An overall good performance was obtained (daily and monthly NSE values of 0.66 and 0.86 for calibration; 0.52 and 0.76 for validation). Water balance and flow components prediction was satisfactory. However, although peak flows were well represented, the model overestimated discharge during low flow periods. Once evaluated, high and low emissions climate change scenarios were simulated using projections based on CMIP3 for both scenarios and for short (2010–2039) and long term (2070–2099) obtained from the Baja California Climate Change Action Program. Noticeable impacts of climate change on river flow were obtained, with runoff reductions around −45% in the short term, but up to −60% in the long term. Main drives seem to be precipitation reduction, in addition to an increasing water loss- in percentage-via evapotranspiration. Aquifer recharge is expected to decrease up to −74%, with a consequent reduction of groundwater flow. We also quantified the differentiating impacts during dry, normal and wet years. The latter was the most affected (annual streamflow reduction up to −72%), especially during winter and spring. On the contrary, a slight runoff increase is expected during dry years, especially during summer. These runoff reductions were supposed to be a huge problem for a region where pressure on water resources is already very strong. Our model framework may provide water managers with an approximation of how climate change possibly can affect water availability, serving as a tool to test further scenarios.