Specific Watershed Research Articles

Linking watershed formation with the phylogenetic distribution of a soil microscopic fungus in Yunnan Province, China

BackgroundPhylogeographic studies have gained prominence in linking past geological events to the distribution patterns of biodiversity, primarily in mountainous regions. However, such studies often focus on plant taxa, neglecting the intricate biogeographical patterns of microbes, particularly soil microbial communities. This article explores the spatial distribution of the nematode-trapping fungus Arthrobotrys oligospora, a widespread microorganism, in a tectonically active region at the southeastern edge of the Qinghai-Tibetan Plateau. By analysing the genetic variation of this fungus alongside the historical structure of major river watersheds, we sought to uncover potential connections between the two. Our study involved sampling 149 strains from 116 sites across six major watersheds in the region.ResultsThe resulting haplotype network revealed five distinct clusters, each corresponding closely to a specific watershed. These clusters exhibited high haplotype diversity and low nucleotide diversity, supporting the notion of watershed-based segregation. Further analysis of haplotypes shared across watersheds provided evidence for three proposed past river connections. In particular, we found numerous shared haplotypes between the Yangtze and Mekong basins, as well as between the Yangtze and the Red basins. Evidence for a Irrawaddy-Salween-Red and a Yangtze-Pearl-Red river connections were also portrayed in our mapping exercise.ConclusionsThese findings emphasize the crucial role of historical geomorphological events in shaping the biogeography of microbial biodiversity, alongside contemporary biotic and abiotic factors. Watershed perimeters emerged as effective predictors of such patterns, suggesting their suitability as analytical units for regional-scale studies. Our study also demonstrates the potential of microorganisms and phylogeographic approaches to complement traditional geological analyses, providing a more comprehensive understanding of past landscape structure and its evolution.

Comparative analysis of data driven rainfall-runoff models in the Kolar river basin

To effectively tackle the challenges posed by climate change, it is crucial to enhance the accuracy of rainfall-runoff models to ensure reliability amidst changing climatic conditions. Neural networks, renowned for their ability to capture complex patterns and relationships within uncertain input and output data, offer valuable tools in this pursuit. This study aims to evaluate the efficacy of two neural network (NN) models: the Radial Basis Function Neural Network (RBFNN) and the Model Tree M5 Neural Network (MTM5NN). These models are assessed both individually and in combination with the Wavelet (WT) data processing technique for rainfall-runoff modeling in the Kolar River watershed located in Madhya Pradesh, India. Fifteen models were developed employing four algorithms: RBFNN models, WRBFNN (RBF model integrating wavelet components of rainfall as inputs), MTM5NN, and WMTM5NN (MT model incorporating wavelet components of rainfall as inputs). Initially, rainfall and runoff data underwent normalization and were applied to RBFNN and MTM5NN networks. Subsequently, time series data for both rainfall and runoff were decomposed using wavelet transforms, resulting in various sub-time series signals such as approximations and decompositions. These derived signals were then utilized as input data for RBFNN and MTM5NN, specifically designated as WRBFNN and WMTM5NN. The most effective model identified was Model 8 of WMTM5NN, which demonstrated R2 values close to 0.97, outperforming the other models. These results underscore the superior performance of the WMTM5NN model, highlighting its effectiveness in achieving heightened accuracy in predicting runoff for this specific watershed.

Quantifying water loss in leaky micro-dam reservoir through water balance analysis and high-resolution water level data modeling

Abstract This study aimed to assess the runoff, recharge, and response of a shallow aquifer to leakage from the Arato micro-dam reservoir (MDR). The assessment was conducted using the Soil Conservation Service Curve Number (SCS-CN), soil moisture balance (SMB), and diver (automatic data logger) measurements in both the MDR and a shallow hand-dug well. Recharge was estimated using the chloride mass balance (CMB) and water table fluctuation (WTF) methods. The results revealed that the annual runoff from the catchment was 48.8 mm, which accounted for approximately 0.71 million m3. The yearly groundwater recharge was estimated to be 104, 92.8, and 100 mm using the SMB, CMB, and WTF methods, respectively. Furthermore, the water balance model of the Arato MDR indicated a leakage rate of 13.2 mm/day. It is noteworthy that the estimated leakage exceeded the seepage initially anticipated during the project's design phase (9,965 m3/year). This research project highlights the significance of utilizing local climatic and physical data from the specific watershed under investigation when planning reservoirs and other water resources. It also underscores the importance of conducting thorough site investigations to accurately quantify hydraulic conductivity for leakage estimation purposes.

Mapping the profiles and underlying driving mechanisms of the antibiotic resistome and microbiome within a subtropical complex river watershed

Antibiotic resistance is an escalating global concern, leading to millions of annual deaths worldwide. Human activities can impact antibiotic resistance gene (ARG) prevalence in aquatic ecosystems, but the intricate interplay between anthropogenic disturbances and river system resilience, and their respective contributions to the dynamics of different river segments, remains poorly understood. In this study, we investigate the antibiotic resistome and microbiome in water and sediment samples from two distinct sub-watersheds within a specific watershed. Results show a decrease in the number of core ARGs downstream in water, while sediments near densely populated areas exhibit an increase. PCoA ordination reveals clear geographic clustering of resistome and microbiome among samples from strong anthropogenic disturbed areas, reservoir areas, and estuary area. Co-occurrence networks highlight a higher connectivity of mobile genetic elements (MGEs) in disturbed areas compared to reservoir areas, presenting a threat to densely populated areas. Water quality parameters and antibiotics concentration were the key factors shaping the ARG profiles in sediment samples from urban regions. Overall, our study reveals distinct patterns of ARGs in sediment and water samples, emphasizing the importance of considering both anthropogenic and natural factors in comprehending and managing ARG distribution in river systems.

Promoting Porosity: Adaptation of Urban Roadways for Flooding and Climate Change

Using environmental and transportation data from a dense urban watershed in Honolulu, Hawaii, the use of porous pavement is investigated as a strategy for mitigation and adaptation to flooding events and increasing resilience to climate change. The potential for water capture to abate pollution and recharge aquifers is also considered. This research is motivated by the increased likelihood of flooding and demands for improved transportation resilience. Based on the impacts from a 2004 flood in Honolulu, installation of permeable asphalt pavements on residential streets with low-to-moderate traffic volumes, and 2% to 5% slope, flooding would be significantly reduced. With the highest absorption rate (90%), 1.8 trillion gal/year could be diverted, while, with a lower absorption rate (50%), 691 billion gallons would be captured. The transformation of roadways, culverts, stormwater infrastructure, and existing drainage systems requires a different approach to planning, designing, construction, and paving (or not) roadways. Adoption of nature-based transportation solutions and integration with low impact development standards by local governments are needed to reduce flood risk and improve environmental quality. Design criteria are reviewed in the context of a specific watershed but also for development and application of methods in other locations. Improved communications and collaboration between researchers, land use planners, and practitioners will further advance resilience through innovation and adaptation to climate change. Porosity is also a factor and requires appreciation for nature and understanding of the seepage and conveyance of new ideas.

Diatoms of Small Water Bodies as Bioindicators in the Assessment of Climatic and Anthropogenic Impacts on the Coast of Tiksi Bay, Russian Arctic

A total of 385 species of diatoms were identified in the phytoplankton of 14 small Arctic tundra water bodies in the vicinity of Tiksi Bay. We found that the species composition of phytoplankton in each lake is strictly individual. The ecological preferences of diatom species in the studied water bodies were determined for more than 90% of the list. Indicator characteristics show a certain response of the species composition of phytoplankton to changes in salinity and organic pollution. Several regularities were revealed in the spatial distribution of diatom communities in the study area in connection with the physicochemical parameters of their habitat, the height of the lake, its remoteness from the seacoast, and belonging to a specific watershed. Statistical mapping of the data on the diversity of communities and the chemical properties of water revealed a strong reaction of the communities of water bodies to point one-time anthropogenic pollution, and also made it possible to assume the influence of summer, northeast winds on the species composition as a climatic factor. The results of the study are important for developing the foundations for monitoring the non-impact (background), ecologically sensitive territory of the Arctic. They are highly relevant for assessing the consequences of local anthropogenic impacts and climate change in the future. Spatial ecological mapping in conjunction with bioindication can be used as a new method for identifying natural and non-natural stress factors.

Comparative Performance Evaluation of HEC-HMS and SWAT Models in Stream Flow Simulation: the Case of Bilate and Gidabo Watersheds, Ethiopia

Many hydrological models have been developed to simulate watershed hydrology. However, identifying the most cost-effective and efficient hydrological models for a specific watershed with reasonable certainty becomes difficult. The purpose of this study was to compare the stream flow prediction efficiency of the HEC-HMS and SWAT models, as well as the associated uncertainty, in the Bilate and Gidabo watersheds. Model-sensitive parameters being identified, they were calibrated and validated. The parameter uncertainties were analyzed using Markov Chain Monte Carlo (MCMC) for HEC-HMS and Sequential Uncertainty Fitting version two (SUF-2) for SWAT. In the case of the HEC-HMS model, the results showed that constant loss rate (CR) was the most sensitive parameter, followed by lag time (LT) for both watersheds. SWAT detected ALPHA_BF in the Bilate Watershed and CN_2 in the Gidabo Watershed as the most sensitive parameters. Overall, both models could adequately simulate the hydrology of both watersheds. Despite their similar modeling capabilities, a comparison analysis revealed that the HEC-HMS model outperformed the SWAT model in simulating streamflow in both watersheds. The findings of this study can help potential model users make risk-informed decisions by selecting a representative model and quantifying associated uncertainty in the modeling field.

Effect of timber removal on the total nutrient fluxes from a freshwater-supplying forested watershed.

Effects of 18% thinning on nutrient fluxes were investigated in a broadleaf forest. Streamflow and suspended sediment were sampled during the calibration and treatment periods for the treatment and control watersheds to determine total nutrient fluxes through bedload sediment and runoff. Streamflow was measured, and water samples were collected from the streams of the watersheds. The volume of the bedload deposited in both weirs' pools was measured, and sediment deposits were sampled at the ends of the calibration and treatment periods. Water and sediment samples were analyzed for calcium (Ca2+ ), magnesium (Mg2+ ), Kjeldahl nitrogen (KN), sodium (Na+ ), potassium (K+ ), iron (Fe3+ ), and sulfur (S2- ). Results showed that there was only a significant increase in KN loss from 0.01 kg/ha to 0.10kg/ha and from 0.04 kg/ha to 2.41 kg/ha in the second and the third post-treatment years, respectively (P < 0.05). Thinning was not intensive to change nutrient outflow in the study site. PRACTITIONER POINTS: The 18% thinning was not intensive enough to increase the total nutrient flux, deteriorate water chemical quality, and hence threaten aquatic life in the stream water. Significant increases were found only in KN outflow after timber removal. If there is no information about the effect of timber harvest on nutrient loss in a specific watershed, the application of evenly distributed low-intensity timber harvest may be a good option to protect stream water quality in forested watersheds. Further investigations are needed about the effects of various timber harvest intensities on physical water quality (odor, color, turbidity, taste, temperature, etc.) and biological characteristics (population and biodiversity of aquatic organisms) of the stream water for making better water management plans.

Comparative Performance Evaluation of HEC-HMS and SWAT Models in Stream Flow Simulation: the Case of Bilate and Gidabo Watersheds, Ethiopia

Many hydrological models have been developed to simulate watershed hydrology. However, identifying the most cost-effective and efficient hydrological models for a specific watershed with reasonable certainty becomes difficult. The purpose of this study was to compare the stream flow prediction efficiency of the HEC-HMS and SWAT models, as well as the associated uncertainty, in the Bilate and Gidabo watersheds. Model-sensitive parameters being identified, they were calibrated and validated. The parameter uncertainties were analyzed using Markov Chain Monte Carlo (MCMC) for HEC-HMS and Sequential Uncertainty Fitting version two (SUF-2) for SWAT. In the case of the HEC-HMS model, the results showed that constant loss rate (CR) was the most sensitive parameter, followed by lag time (LT) for both watersheds. SWAT detected ALPHA_BF in the Bilate Watershed and CN_2 in the Gidabo Watershed as the most sensitive parameters. Overall, both models could adequately simulate the hydrology of both watersheds. Despite their similar modeling capabilities, a comparison analysis revealed that the HEC-HMS model outperformed the SWAT model in simulating streamflow in both watersheds. The findings of this study can help potential model users make risk-informed decisions by selecting a representative model and quantifying associated uncertainty in the modeling field.

HYDROLOGICAL ANALYSIS OF THE WATERSHED OF AN NAJAF PROVINCE BY GIS

The analysis of the watershed gives the surface area of land that rain streamed arrived in the river. The modern method to analyze the catchment is the ArcGIS program based on the Digital Elevation Model (DEM). The study area is An Najaf province, which area equaled about 27675 square kilometers. The HECGeoHMS (Hydrologic Engineering Center's Hydrologic Modeling System) is the link program on the ArcMap software that abled by serious steps to analyze the specific watershed. The auto analysis of the watershed area gives four basins for each outlet points located on the distributary Euphrates river. These four basins consisted of multi sub-basins and streams of rain flow. Basin 4 has the most significant volume, about 11.4% of the total case area of the basin, and the average slope is 3.2%. According to the amount of accumulative rainwater, basin 4 is essential when any obstruction is constructed at the end of the outlet point in the stream. This location of the construct is used to prevent the sediment in the Euphrates river and to avoid surface soil degradation. The arrangement of importance basin based on the advantage of water using to give maximum discharge and low evaporation is basin four at the first, basin two at the second.

Delving into the Divisive Waters of River Basin Planning in Bolivia: A Case Study in the Cochabamba Valley

River basin planning in Bolivia is a relatively new endeavor that is primed for innovation and learning. One important learning opportunity relates to connecting watershed planning to processes within other planning units (e.g., municipalities) that have water management implications. A second opportunity relates to integrating watershed management, with a focus on land-based interventions, and water resources management, with a focus on the use and control of surface and groundwater resources. Bolivia’s River Basin Policy and its primary planning instrument, the River Basin Master Plan (PDC in Spanish), provide the relevant innovation and learning context. Official guidance related to PDC development lacks explicit instructions related to the use of analytical tools, the definition of spatially and temporally dis-aggregated indicators to evaluate specific watershed and water management interventions, and a description of the exact way stakeholders engage in the evaluation process. This paper describes an effort to adapt the tenets of a novel planning support practice, Robust Decision Support (RDS), to the official guidelines of PDC development. The work enabled stakeholders to discern positive and negative interactions among water management interventions related to overall system performance, hydrologic risk management, and ecosystem functions; use indicators across varying spatial and temporal reference frames; and identify management strategies to improve outcomes and mitigate cross-regional or inter-sectorial conflicts.

Hydrogeochemical and environmental water quality standards in the overlap between high mountainous natural protected areas and copper mining activities (Mapocho river upper basin, Santiago, Chile)

Natural hydrogeochemical backgrounds or signatures from rivers around the world show great differences depending on the geological and hydrological settings where the specific watershed is placed. This fact is especially relevant and notorious, when the metallic content of waters draining hydrothermally-altered high-mountainous regions is considered. The present study offers a hydrogeochemical perspective to improve the generation of Environmental Water Quality Standards (EWQS) in mineralized high mountain regions comprised by rivers unaffected and affected by acid rock drainage (ARD). To this end, the complex and versatile reality at the Mapocho river upper basin (comprised by a natural ARD affected sub-basin, a mining intervened sub-basin and a third sub-basin with Andean unaffected waters) was used to evaluate the effect of seasonal and long-term climatic variations on hydrothermally-altered high-mountainous regions.In addition, 22 different environmental water quality standards (EWQS) from different countries around the globe were analyzed. This information was used to define what could be understood as “an acceptable water quality for environmental use”. Also, the obtained elemental concentration and physicochemical ranges were compared with the results obtained at the Mapocho upper basin to assess the importance of regional and local geochemical backgrounds on the generation of EWQS. As a result of this information generation, compilation, analyses and intercomparison, several recommendations to consider during the generation of EWQS at heterogenous high mountainous watersheds comprised by both ARD affected and unaffected sub basins were made. Special attention was paid to the incorporation of seasonal variations and long-term effects (climate change) on the generation of more realistic and useful EWQS.

A System for Assessing and Forecasting the Bioproductivity of Lacustrine-Type Ecosystems

A system has been developed for diagnosing the biological production of lake ecosystems with input parameters: geographic latitude, specific watershed, normal annual air temperature, annual precipitation, mean and maximal depth of the water body, water residence time in it, and the values of water color index and daily assimilation number of phytoplankton chlorophyll a, averaged over vegetation season. Several lakes and reservoirs situated in different geographic zones of RF (from Northwest to the Far East) have been used to forecast the annual production of terrestrial vegetation in the drainage basin and the key groups of aquatic organisms: primary producers, bacterioplankton, and consumers, including fishes.

Evaluating the Performance of HEC-HMS and SWAT Hydrological Models in Simulating the Rainfall-Runoff Process for Data Scarce Region of Ethiopian Rift Valley Lake Basin

A number of physically-based and distributed watershed models have been developed to model the hydrology of the watershed. For a specific watershed, selecting the most suitable hydrological model is necessary to obtain good simulated results. In this study, two hydrologic models, Soil and Water Assessment Tool (SWAT) and Hydrological Engineering Centre-The Hydrologic Modeling System (HEC-HMS), were applied to predict streamflow in Katar River basin, Ethiopia. The performances of these two models were compared in order to select the right model for the study basin. Both models were calibrated and validated with stream flow data of 11 years (1990-2000) and 7 years (2001-2007) respectively. Nash-Sutcliffe Error (NSE) and Coefficient of Determination (R2) were used to evaluate efficiency of the models. The results of calibration and validation indicated that, for river basin Katar, both models could simulate fairly well the streamflow. SWAT gave the model performance with the R2 > 0.78 and NSE > 0.67; and the HEC-HMS model provided the model performance with the R2 > 0.87 and NSE > 0.73. Hence, the simulated streamflow given by the HEC-HMS model is more satisfactory than that provided by the SWAT model.

Searching for an Optimized Single-objective Function Matching Multiple Objectives with Automatic Calibration of Hydrological Models

In the calibration of hydrological models, evaluation criteria are explicitly and quantitatively defined as single- or multi-objective functions when utilizing automatic calibration approaches. In most previous studies, there is a general opinion that no single-objective function can represent all important characteristics of even one specific hydrological variable (e.g., streamflow). Thus hydrologists must turn to multi-objective calibration. In this study, we demonstrated that an optimized single-objective function can compromise multi-response modes (i.e., multi-objective functions) of the hydrograph, which is defined as summation of a power function of the absolute error between observed and simulated streamflow with the exponent of power function optimized for specific watersheds. The new objective function was applied to 196 model parameter estimation experiment (MOPEX) watersheds across the eastern United States using the semi-distributed Xinanjiang hydrological model. The optimized exponent value for each watershed was obtained by targeting four popular objective functions focusing on peak flows, low flows, water balance, and flashiness, respectively. Results showed that the optimized single-objective function can achieve a better hydrograph simulation compared to the traditional single-objective function Nash-Sutcliffe efficiency coefficient for most watersheds, and balance high flow part and low flow part of the hydrograph without substantial differences compared to multi-objective calibration. The proposed optimal single-objective function can be practically adopted in the hydrological modeling if the optimal exponent value could be determined a priori according to hydrological/climatic/landscape characteristics in a specific watershed.

Water Quality Evaluation of the Yangtze River in China Using Machine Learning Techniques and Data Monitoring on Different Time Scales

Unlike developed countries, China has a nationally unified water environment standard and a specific watershed protection bureau to perform water quality evaluation. It is a major challenge to assess the water quality of a large watershed at a wide spatial scale and to make decisions in a scientific way. In 2016, weekly and real-time data for four monitoring indicators (pH, dissolved oxygen, permanganate index, and ammonia nitrogen) were collected at 21 surface water sections (sites) of the Yangtze River Basin, China. Results showed that one site had a relatively low Site Water Quality Index and was polluted for 12 weeks meanwhile. By using expectation-maximization clustering and hierarchical clustering algorithms, the 21 sites were classified. Variable spatiotemporal distribution characteristics for water quality and pollutants were found; some sites exhibited similar water quality variations on the weekly scale, but had different yearly grades. The results revealed polluted water quality for short periods and abrupt anomalies, which imply potential pollution sources and negative effects on water ecosystems. Potential spatio-temporal water quality characteristics, explored by machine learning methods and evidenced by time series and statistical models, could be applied in environmental decision support systems to make watershed management more objective, reliable, and powerful.

Analysis of flow-sediment rating curve hysteresis based on flow and sediment travel time estimations

A flow-sediment rating curve is used to describe the relation between flow discharge and suspended-sediment concentration for a specific location. Five types of flow-sediment rating curves - single-valued line, clockwise loop, counterclockwise loop, single-valued line plus loop, and figure eight - were found to rely on the flow and available sediment arriving at the measuring site. In this study, equations for flow and sediment travel time were derived according to soil, rainfall, and watershed geomorphologic characteristics. The hysteresis of the rating curve was related to the travel times by a series of numerical tests. Field data collected from the Goodwin Creek Experimental Watershed, Mississippi, United States were used to verify the proposed rating curve hysteresis analysis. The results indicate that when the flow travel time is more extended than the sediment travel time, the rating curve shows a clockwise loop. A counterclockwise loop in the rating curve shows that the flow travel time is less extended than the sediment travel time. If the flow travel time exceeds the sediment travel time in specific runoff states and is less than the sediment travel time in other runoff states, then a single line plus a loop rating curve or a figure-eight rating curve is observed. The criterion for the model parameters to obtain equalization of the flow and sediment travel times was derived, which can identify the type of flow-sediment rating curve in a specific watershed.

Integrated Water Resources Conservation Management for a Sustainable Food Security

Many of Indonesia’s watersheds are reaching a critical stage. As a result of higher rates of erosion and sedimentation, the number of critical watersheds in Indonesia has increased from 22 in 1984 to 58 in 2000 and in 2014 this number has reached 108. This result in food security is being threatened because there is insufficient water available for agriculture purposes due to catchment degradation, especially in the upper parts of the watersheds. At the same time, Indonesia’s new government focused its national development programs on food security for the next five years. For these reasons Indonesia’s National Development Planning Agency believes that it is timely to develop a national policy on Integrated Water Conservation Management (IWCM). To provide the rationale and suggested content for such a national policy, this paper has been prepared based onfocused group discussions with relevant interests at the national and regional levels. To obtain specific input from regional stakeholders, workshops were held in Medan, Yogyakarta, Banjarmasin, Nusa Tenggara Barat and Makassar as well as line agencies based in the state capital of Jakarta from October 2014 to March 2015. At the landscape level, the formulation of national policy on IWCM was based on integrated watershed management analysis as water resources within a specific watershed are integrated into other resources within an ecosystem. This action research recommends the following: a) integrating the IWCM into the regular regional development activities, b) encouraging local agreements on water resource conservation including local adat communities, c) formulating attractive economic incentives in implementing IWCM programs, d) using corporate social responsibility and payment for environment services funding to boost water resource conservation program at village level, and e) involving actively women in the IWCM programs. Considering that socio-cultural aspects are also playing an important role in the IWCM, a national-level of institutional arrangement on IWCM will also be proposed. Keywords: IWCM; food security; green and blue water; watershed; institutional arrangement; Indonesia

Development of a Component-Based Modeling Framework for Agricultural Water-Resource Management

Because hydrologic responses of an agricultural watershed are influenced by many natural and man-made factors including pond/reservoir, management practices, and/or irrigation/drainage, strategies of hydrological modeling for the watershed must be case-dependent and thus carefully designed to effectively reflect their roles as critical hydrologic components in simulation processes. In this study, we propose a component-based modeling framework that accommodates a flexible modeling approach to consider a variety of hydrologic processes and management practices, especially irrigation-reservoir operation and paddy-farming practices, in watershed-scale modeling. The objectives of this study are twofold: to develop a COmponent-based Modeling Framework for Agricultural water-Resources Management (COMFARM) using an object-oriented programming technique, and to evaluate its applicability as a modeling tool to predict the responses of an agricultural watershed characterized with diverse land uses in a case study. COMFARM facilitates quick and easy development of watershed-specific hydrologic models by providing multiple interchangeable simulation routines for each hydrologic component considered. COMFARM is developed with the JAVA programming language, using Eclipse software. The framework developed in this study is applied to simulating hydrologic processes of the Seon-Am irrigation-district watershed consisting primarily of reservoir-irrigated rice paddies in South Korea. The application study clearly demonstrates the applicability of the framework as a convenient method to build models for hydrologic simulation of an agricultural watershed. The newly developed modeling framework, COMFARM is expected to serve as a useful tool in watershed management planning by allowing quick development of case-oriented analysis tools and evaluation of management scenarios customized to a specific watershed.

Comparative Study of Evolutionary Algorithms for the Automatic Calibration of the Medbasin-D Conceptual Hydrological Model

The calibration of a hydrological model is an important task for obtaining accurate runoff simulation results for a specific watershed. Several optimisation algorithms have been applied during the last years for the automatic calibration of conceptual rainfall-runoff (CRR) models. The aim of this study is to compare the effectiveness and the efficiency of three evolutionary algorithms, namely the Shuffled Complex Evolution (SCE), the Genetic Algorithms (GA) and the Evolutionary Annealing-Simplex (EAS), for the calibration of the Medbasin-D daily CRR model. An improved calibration approach of Medbasin-D is presented, including a batch-processing module which enables the implementation of coupled simulation-optimisation routines. The enhanced Medbasin calibration module is employed in a watershed of the island of Crete (Greece), using several objective functions in order to test the optimisation algorithms under different hydrological flow conditions. The results reveal that, in terms of effectiveness, SCE and EAS performed equally well, while GA provided slightly worse optimal solutions. However, GA was computationally more efficient than SCE and EAS. Despite the discrepancies among the optimisation runs, the simulated hydrographs had a very similar response for the optimal parameter sets obtained by the same calibration criteria, indicating that all tested optimisation methods produce equally successful results with Medbasin-D model. Additionally, the selected objective function seems to have a more decisive effect on the final simulation outcomes.