Description: Water, Vol. 10, Pages 1311: Season-Dependent Hedging Policies for Reservoir Operation—A Comparison Study Water doi: 10.3390/w10101311 Authors: Nikhil Bhatia Roshan Srivastav Kasthrirengan Srinivasan During periods of significant water shortage or when drought is impending, it is customary to implement some kind of water supply reduction measures with a view to prevent the occurrence of severe shortages (vulnerability) in the near future. In the case of operation of a water supply reservoir, this reduction of water supply is affected by hedging schemes or hedging policies. This research work aims to compare the popular hedging policies: (i) linear two-point hedging; (ii) modified two-point hedging; and, (iii) discrete hedging based on time-varying and constant hedging parameters. A parameterization-simulation-optimization (PSO) framework is employed for the selection of the parameters of the compromising hedging policies. The multi-objective evolutionary search-based technique (Non-dominated Sorting based Genetic Algorithm-II) was used to identify the Pareto-optimal front of hedging policies that seek to obtain the trade-off between shortage ratio and vulnerability. The case example used for illustration is the Hemavathy reservoir in Karnataka, India. It is observed that the Pareto-optimal front that was obtained from time-varying hedging policies show significant improvement in reservoir performance when compared to constant hedging policies. The variation in the monthly parameters of the time-variant hedging policies shows a strong correlation with monthly inflows and available water.

Description: Water, Vol. 10, Pages 1308: Impact of Uncertainty of Floodplain Digital Terrain Model on 1D Hydrodynamic Flow Calculation Water doi: 10.3390/w10101308 Authors: Adam Kiczko Dorota Mirosław-Świątek This study investigates the effect of the Digital Terrain Model (DTM) uncertainty effect on the output of a 1D flow model. The analysis is performed for the lowland river Biebrza, covered with dense wetland vegetation, with a high uncertainty of terrain elevations. The DTM uncertainty is modeled in two ways: (1) accounting for the uncertainty spatial dependency on the basis of the correlogram function and (2) neglecting the correlation of the elevation points. The model explanation of water levels improves when elevation uncertainty is being included. Without the elevation uncertainty, the model provided a good fit only for peak flows, with uncertainty also representation of lower flows is better. It was shown that the correlation of the elevation uncertainty had a noticeable effect on the modeling outcomes, especially for near bankfull flows, where for the uncorrelated case water levels were underestimated by 5 cm, comparing to the correlated case. The effect was also present for inundation extents, obtained by an interpolation of computed water levels. The correlation of the elevation uncertainty strongly affects estimates of standard deviations of computed water levels, which were almost twice smaller when correlation was neglected. In the result, only when the correlation of the elevation uncertainty was included, it was possible to obtain confidence bands that enclosed observation points.

Description: Water, Vol. 10, Pages 1298: Denitrification-Potential Evaluation and Nitrate-Removal-Pathway Analysis of Aerobic Denitrifier Strain Marinobacter hydrocarbonoclasticus RAD-2 Water doi: 10.3390/w10101298 Authors: Dedong Kong Wenbing Li Yale Deng Yunjie Ruan Guangsuo Chen Jianhai Yu Fucheng Lin An aerobic denitrifier was isolated from a long-term poly (3-hydroxybutyrate-co-3-hydroxyvalerate) PHBV-supported denitrification reactor that operated under alternate aerobic/anoxic conditions. The strain was identified as Marinobacter hydrocarbonoclasticus RAD-2 based on 16S rRNA-sequence phylogenetic analysis. Morphology was observed by scanning electron microscopy (SEM), and phylogenetic characteristics were analyzed with the API 20NE test. Strain RAD-2 showed efficient aerobic denitrification ability when using NO3−-N or NO2−-N as its only nitrogen source, while heterotrophic nitrification was not detected. The average NO3−-N and NO2−-N removal rates were 6.47 mg/(L·h)and 6.32 mg/(L·h), respectively. Single-factor experiments indicated that a 5:10 C/N ratio, 25–40 °C temperature, and 100–150 rpm rotation speed were the optimal conditions for aerobic denitrification. Furthermore, the denitrifying gene napA had the highest expression on a transcriptional level, followed by the denitrifying genes nirS and nosZ. The norB gene was found to have significantly low expression during the experiment. Overall, great aerobic denitrification ability makes the RAD-2 strain a potential alternative in enhancing nitrate management for marine recirculating aquaculture system (RAS) practices.

Description: Water, Vol. 10, Pages 1299: Assessing the Impact of Site-Specific BMPs Using a Spatially Explicit, Field-Scale SWAT Model with Edge-of-Field and Tile Hydrology and Water-Quality Data in the Eagle Creek Watershed, Ohio Water doi: 10.3390/w10101299 Authors: Katherine R. Merriman Prasad Daggupati Raghavan Srinivasan Chad Toussant Amy M. Russell Brett Hayhurst The Eagle Creek watershed, a small subbasin (125 km2) within the Maumee River Basin, Ohio, was selected as a part of the Great Lakes Restoration Initiative (GLRI) “Priority Watersheds” program to evaluate the effectiveness of agricultural Best Management Practices (BMPs) funded through GLRI at the field and watershed scales. The location and quantity of BMPs were obtained from the U.S. Department of Agriculture-Natural Resources Conservation Service National Conservation Planning (NCP) database. A Soil and Water Assessment Tool (SWAT) model was built and calibrated for this predominantly agricultural Eagle Creek watershed, incorporating NCP BMPs and monitoring data at the watershed outlet, an edge-of-field (EOF), and tile monitoring sites. Input air temperature modifications were required to induce simulated tile flow to match monitoring data. Calibration heavily incorporated tile monitoring data to correctly proportion surface and subsurface flow, but calibration statistics were unsatisfactory at the EOF and tile monitoring sites. At the watershed outlet, satisfactory to very good calibration statistics were achieved over a 2-year calibration period, and satisfactory statistics were found in the 2-year validation period. SWAT fixes parameters controlling nutrients primarily at the watershed level; a refinement of these parameters at a smaller-scale could improve field-level calibration. Field-scale modeling results indicate that filter strips (FS) are the most effective single BMPs at reducing dissolved reactive phosphorus, and FS typically decreased sediment and nutrient yields when added to any other BMP or BMP combination. Cover crops were the most effective single, in-field practice by reducing nutrient loads over winter months. Watershed-scale results indicate BMPs can reduce sediment and nutrients, but reductions due to NCP BMPs in the Eagle Creek watershed for all water-quality constituents were less than 10%. Hypothetical scenarios simulated with increased BMP acreages indicate larger investments of the appropriate BMP or BMP combination can decrease watershed level loads.

Description: Water, Vol. 10, Pages 1302: Long-Term Suspended Sediment Concentrations and Loads from a Relatively Undisturbed Agroforested Catchment in the Northwest of the Iberian Peninsula Water doi: 10.3390/w10101302 Authors: M. Luz Rodríguez-Blanco M. Mercedes Taboada-Castro M. Teresa Taboada-Castro The suspended sediment dynamics in small catchments are difficult to estimate accurately because they result from the coupling of complex processes occurring at different scales. In this study, the dynamics of suspended sediment concentrations (SSC) and loads were assessed in an agroforested humid catchment in NW Spain, based on a long-term rainfall, discharge and suspended sediment dataset (12 hydrological years) from high-frequency monitoring. The results highlight the episodic nature of sediment transport in the study area, given that about 78% of SS was exported over 10% of the study period. The SS transport was related to runoff generation and flooding, although sediment availability also played an important role in SS transport. The SS load was mainly driven by high-magnitude rainfall events, while intense rainfall episodes generated high SSC peaks. The mean annual suspended sediment yield was relatively low from a quantitative stand point (10 Mg km−2 y−1); however, during 11% of the monitoring, SS concentrations exceeding the threshold threatened surface water quality (Freshwater Fish Directive 78/659/EEC and Directive 75/440/EEC), mainly during runoff events, indicating the need to adopt management practices in order to reduce or mitigate sediment loss during such episodes.

Description: Water, Vol. 10, Pages 1304: Baseflow Contribution to Streamflow and Aquatic Habitats Using Physical Habitat Simulations Water doi: 10.3390/w10101304 Authors: Byungwoong Choi Hyeongsik Kang Woong Hee Lee A scientific understanding of the baseflow contribution to streams and watershed processes is critical when dealing with water policy and management issues. However, most previous studies involving physical habitat simulation have been performed without considering the seepage of water from the underground into streams. Motivated by this, herein, we report an investigation of the impact of baseflow using physical habitat simulations for both dominant fish and benthic macroinvertebrate. The study area was located along the reach of the Ungcheon Stream, located 16.50 km downstream and 11.75 km upstream from the Boryeong Dam in the Republic of Korea. For the physical habitat simulation, Zacco platypus and Baetis fuscatus were selected as the target fish and benthic macroinvertebrate, respectively. The HydroGeoSphere (HGS) model (Aquanty Inc., Waterloo, ON, Canada) and the River2D model (Version 0.95a, University of Alberta, Edmonton, AB, Canada) were used for hydrologic and hydraulic simulations, respectively. The Habitat Suitability Index (HSI) model was used for the habitat simulations. Three habitat variables, flow depth, velocity, and substrate, were used. To assess the impact of baseflow, this study performed a physical habitat simulation using each representative discharge, with and without considering baseflow. It was found that the baseflow effects significantly increase the habitat suitability in the study reach. To restore the aquatic habitat, a scenario for modifying dam operations through natural flow patterns is presented using the Building Block Approach (BBA). In the study, the adjusted minimum flow allocation concept was used. It was revealed that the modified dam operations significantly increased the Weighted Usable Area (WUA) by about 48% for both target species. The results indicate that modifying the dam operations through restoration to natural flow regimes but also through inclusion of the baseflow are advantageous to aquatic fish habitats.

Description: Water, Vol. 10, Pages 1303: A New Comprehensive Evaluation Method for Water Quality: Improved Fuzzy Support Vector Machine Water doi: 10.3390/w10101303 Authors: Wei Shan Shensheng Cai Chen Liu With the pressure of population growth and environmental pollution, it is particularly important to develop and utilize water resources more rationally, safely, and efficiently. Due to safety concerns, the government today adopts a pessimistic method, single factor assessment, for the evaluation of domestic water quality. At the same time, however, it is impossible to grasp the timely comprehensive pollution status of each area, so effective measures cannot be taken in time to reverse or at least alleviate its deterioration. Thus, the main propose of this paper is to establish a comprehensive evaluation model of water quality, which can provide the managers with timely information of water pollution in various regions. After considering various evaluation methods, this paper finally decided to use the fuzzy support vector machine method (FSVM) to establish the model that is mentioned above. The FSVM method is formed by applying the membership function to the support vector machine. However, the existing membership functions have some shortcomings, so after some improvements in these functions, a new membership function is finally formed. The model is then tested on the artificial data, UCI dataset, and water quality evaluation historical data. The results show that the improvement is meaningful, the improved fuzzy support vector machine has good performance, and it can deal with noise and outliers well. Thus, the model can completely solve the problem of comprehensive evaluation of water quality.

Description: Water, Vol. 10, Pages 1301: Evaluation of Hydraulic Performance Characteristics of a Newly Designed Dynamic Fluidic Sprinkler Water doi: 10.3390/w10101301 Authors: Xingye Zhu Alexander Fordjour Shouqi Yuan Frank Dwomoh Daoxing Ye A newly designed dynamic fluidic sprinkler was tested with different types of nozzles at different operating pressures. Therefore, the aim of this paper was to evaluate the hydraulic performance of a newly designed dynamic fluidic sprinkler. MATLAB R2014a software was employed to establish the computational program for the computed uniformity. Droplet sizes were determined using a Thies Clima Laser Precipitation Monitor. Results showed that the nozzle with a diameter of 5.5 mm gave the highest coefficient of uniformity value of 86% at a low pressure of 150 kPa. The comparison of water distribution profiles for the nozzle sizes (2, 3, 4, 5.5, 6 and 7 mm) at different operating pressures (100, 150, 200, 250 and 300 kPa) showed that a 5.5-mm nozzle size produced a parabola-shaped profile at 150 kPa. The mean droplet diameters for the nozzles sizes of 2, 3, 4, 5.5, 6 and 7 mm ranged from 0 to 4.2, 0 to 3.7, 0 to 3.6, 0 to 3.2, 0 to 0.5 and 0 to 3.8 mm, respectively. The comparison of droplet size distributions showed that 5.5 mm had the optimum droplet diameter of 3.2 mm. The largest droplet sizes had a maximum value of 4.0 for a 2-mm nozzle size. For all the nozzles sizes, 5.5 mm produced better results for hydraulic performance, which can significantly improve the performance and save water for crop production in sprinkler-irrigated fields.

Description: Water, Vol. 10, Pages 1300: Identifying Surface Runoff Pathways for Cost-Effective Mitigation of Pollutant Inputs to Drinking Water Reservoir Water doi: 10.3390/w10101300 Authors: Jolanta Dąbrowska Paweł B. Dąbek Iwona Lejcuś Surface runoff (overland flow) is the main element of the water cycle and is also crucial in the delivery of phosphorus and nitrogen from catchments to water bodies. Watercourses and reservoirs in agricultural catchments are particularly vulnerable to the delivery of biogenic compounds via surface runoff. Forested riparian buffers are considered effective in reducing nutrients and sediment loads in runoff from agricultural areas. Regrettably, the concentration of surface runoff may significantly limit the buffering capacity of vegetation strips, as channelised overland flow tends to avoid buffers without making optimal use of their ability to retain nutrients and sediment. The aim of the undertaken research was to delineate surface runoff pathways from surrounding areas to a drinking water reservoir as well as to identify potential concentration spots of overland flow. The research was conducted for the Dobromierz drinking water reservoir (GPS N: 50°54′27″, E: 16°14′37″). The reservoir is situated in a submountain catchment, where rainfall is an important factor taking part in driving diffuse P and N loads from land to water. Presented GIS-based method using high resolution Digital Terrain Model obtained from Light Detection and Ranging (LiDAR) allowed to determine areas with a tendency for high accumulation (concentration) of overland flow in the direct catchment of the reservoir. As main surface runoff areas, three sites each exceeding 100 ha were designated. The analysis of spatial data also allowed to establish the risk of agricultural diffuse pollution transfer via channelised overland flow to the reservoir from individual accumulation areas. It was found that in the forested part of the catchment (serving as a riparian buffer) there is no visible tendency for concentration of surface runoff, but simultaneously the vegetation strip does not prevent the transfer of runoff waters from agricultural areas through the privileged pathways of concentrated flow.

Description: Water, Vol. 10, Pages 1297: A Regional-Scale Landslide Warning System Based on 20 Years of Operational Experience Water doi: 10.3390/w10101297 Authors: Samuele Segoni Ascanio Rosi Riccardo Fanti Angela Gallucci Antonio Monni Nicola Casagli SIGMA is a regional landslide warning system based on statistical rainfall thresholds that operates in Emilia Romagna (Italy). In this work, we depict its birth and the continuous development process, still ongoing, after two decades of operational employ. Indeed, a constant work was carried out to gather and incorporate in the modeling new data (extended rainfall recordings, updated landslides inventories, temperature and soil moisture data). The use of these data allowed for regular updates of the model and some conceptual improvements, which consistently increased the forecasting effectiveness of the warning system through time. Landslide forecasting at regional scale is a very complex task, but this paper shows that, as time passes by, the systematic gathering and analysis of new data and the continuous progresses of research activity, uncertainties can be progressively reduced. Thus, by the setting up of forward-looking research programs, the performances and the reliability of regional scale warning systems can be increased with time.