Pilot Basin Research Articles

Two different soil erosion modeling approaches in a small experimental area

AbstractThe models compared in this study were applied to a catchment located in the western part of Slovakia in order to analyze and compare the amount of soil loss in different periods. Using of the empirical model universal soil loss equation, the average annual soil loss in the pilot basin was modeled for 2015–2020. The universal soil loss equation includes a topographic factor modeled using the USLE2D external model. In order to compare the empirical model and the physically-based model a continual sequence of individual rainfall events was created and used as an input to the physically-based EROSION-3D model. The results reflect different behaviors of erosion processes in a catchment together with a comparison between empirical and physically-based approaches.

Evolution of freshwater availability in a climate‐changing Mediterranean context: The case of Umbria region, central Italy

AbstractFreshwater availability is the litmus test of the ongoing global warming, but local effects in relation to larger scale behaviours are often ambiguous. In this study, 19 indicators derived by historical rainfall and temperature records have been used to reconstruct climatic trends over the Umbria region (central Italy). The scenario emerging from observations of the last 70–100 years consists in increasing air temperatures and decreasing yearly precipitation depths, which are differently distributed over the 12 months with respect to the past. As a second step, the response in terms of freshwater availability has been assessed by analysing runoff and groundwater records. A clear reduction in yearly water volumes flowing through the outlet stations of five pilot basins during the last century (1927–2020) has been found, quantified in a median loss rate of equivalent surface water thickness of −1.62 mm/year. Monthly mean groundwater levels show a slight increasing trend for most of the monitoring stations, but such an analysis has been carried out over a limited and more recent period (2006–2020). Hence, it can be affected by the uncertainty commonly associated to the interpretation of trend analyses referring to short temporal windows. This last critical point is strengthened by an analysis of the runoff volume limited to the period 2006–2020 from which, in contrast with the results provided by the aforementioned long‐term investigation, an increasing trend has been derived.

A Participatory Approach to Exploring Nexus Challenges: A Case Study on the Pinios River Basin, Greece

The conservation of natural resources is indispensable for supporting sustainable development. Water–Energy–Food–Ecosystem (WEFE) nexus management is widely acknowledged as the utmost priority of our time. Considering the specificities of the different nexus sectors, conflicting views of sustainability may arise from different stakeholders. This paper presents and analyses an effective stakeholders’ participation strategy aiming at identifying WEFE challenges in the Pinios River Basin (PRB), the most agriculturally productive and natural resource-stressed basin of Greece. The presented methodology was developed in the context of a Learning and Action Alliance (LAA) scheme adopted by the H2020 REXUS project, intended to support resilient nexus system management with the engagement of stakeholders. The proposed comprehensive methodology comprises multiple phases, including “framing”, “mapping”, “involvement”, “co-production”, and “sharing” phases. The involvement phase is the most interactive one, including the organisation and outputs of efficient crowdsourcing theme sessions organised in the framework of the first REXUS PRB stakeholders’ workshop. This paper illustrates and analyses stakeholders’ perceptions regarding nexus status in the PRB and reveals the most critical challenges in the pilot basin, along with their interdependencies and correlations. The determination of nexus challenges insights by stakeholders could significantly contribute to redefining policies so that they align with sustainable development aims. This methodology is proposed to form the baseline strategy in stakeholders’ engagement for future nexus management studies.

Critical areas for sediment delivery to the Chubut River, Patagonia Argentina: geomorphological evidence from the Sagmata pilot basin

ABSTRACT Sediment discharge events in the lower basin of the Chubut River (Patagonia, Argentina) associated with rainfall events generate serious problems for drinking water purification of more than 250,000 inhabitants and the support of livestock farming activity of about 42,000 ha in the region. Identifying the areas of potential sediment contribution to the Chubut River and the conditions necessary for erosion and sediment transfer is of vital importance to mitigate the negative impact of sediment discharge into the river and to establish water management plans. We conducted a detailed geomorphological study in a 110 km2 tributary watershed of the Chubut River (Sagmata pilot Basin), and identify potential sediment production zones. We based our analyzes on concomitant studies that indicate that the sediment remobilization is linked to the location of the drainage networks, especially in regions associated with badlands and erosional scarps formed on Paleogene continental deposits.

Assimilation of Ground and Satellite Snow Observations in a Distributed Hydrologic Model for Water Supply Forecasting

AbstractRunoff from the Upper Colorado River Basin (UCRB) is an important water resource in the western United States. The majority of annual runoff is derived from spring snowmelt, and therefore April–July water supply volume (WSV) forecasts produced by the Colorado Basin River Forecast Center are critical to basin water management. The primary objective of this study was to evaluate the impact of snow data assimilation (DA) in a distributed hydrologic model on WSV forecasting error and skill in headwater catchments of the UCRB. To do this, a framework was built to use the Localized Ensemble transform Kalman filter to update modeled snow water equivalent (SWE) states in the Hydrology Laboratory‐Research Distributed Hydrologic Model with SNOTEL SWE observations and spatially and temporally complete MODIS Snow Covered‐Area and Grain size data. The DA approach was assessed by evaluating ensemble streamflow prediction forecasts over a 20‐year period for 23 catchments in the UCRB. Overall, the DA approach improved water supply forecast skill in 80% of pilot basins with an average improvement in the median continuous rank probability skill score of 4%. A research‐to‐operations transition was facilitated by automating the implementation of the DA approach. This work demonstrates the capacity for gridded and point snow products to be used to objectively update model states in an operational forecasting setting.

Water Footprint and Virtual Water Trade of Maize in the Province of Buenos Aires, Argentina

Agriculture is the largest fresh water consuming sector, and maize is the most produced and consumed crop worldwide. The water footprint (WF) methodology quantifies and evaluates the water volumes consumed and polluted by a given crop, as well as its impacts. In this work, we quantified for the first time the green WF (soil water from precipitation that is evapotranspired) and the green virtual water exports of maize from Buenos Aires province, Argentina, during 2016–2017, due to the relevance of this region in the world maize trade. Furthermore, at local level, we quantified the green, blue (evapotranspired irrigation), and grey (volume of water needed to assimilate a pollution load) WF of maize in a pilot basin. The green WF of maize in the province of Buenos Aires ranged between 170 and 730 m3/ton, with the highest values in the south following a pattern of yields. The contribution of this province in terms of green virtual water to the international maize trade reached 2213 hm3/year, allowing some water-scarce nations to ensure water and water-dependent food security and avoid further environmental impacts related to water. At the Napaleofú basin scale, the total WF of rainfed maize was 358 m3/ton (89% green and 11% grey) and 388 m3/ton (58% green, 25% blue, and 17% grey) for the irrigated crop, showing that there is not only a green WF behind the exported maize, but also a Nitrogen-related grey WF.

Stakeholder Voice in Water Resource Planning

Stakeholder engagement for natural resource management at the state and local levels has become an important governance practice. This study examines the association of individual traits (aggressive communication, comfort with technology, and argumentativeness) with stakeholder participant voice in a water basin planning virtual meeting setting. Individual participants of the Edisto River Basin Council (RBC) meetings are the subject of the study. South Carolina decentralized water planning to the river basin level, creating RBCs and appointing interested and relevant stakeholders as members. While the river basin planning process did not envisage virtual (Zoom) meetings for the regular meetings of the RBC, the COVID pandemic required this to begin the planning process. Moreover, meeting participants possess diverse interests, powers, and individual traits that may affect the use of voice and engagement. There is well-established literature on stakeholder participation in resource planning. However, there are gaps in the literature regarding use of voice in virtual meeting settings in water resources planning, especially in settings like water-abundant areas in the Southeastern United States. Using the Edisto RBC as a pilot basin and quantitative surveys, preliminary results found that while RBC participants were on average comfortable with technology, they generally avoided conflict, they exhibited average communication apprehension in a meeting environment, and virtual meetings appear to limit participant’s use of voice. Consequently, meeting planners must recognize that not all participants express themselves optimally in virtual meeting settings. In this vein, planners must work to develop opportunities for as much active engagement and sharing as possible.

Modelling water resources for planning irrigation development in drought-prone southern Chile

ABSTRACT To foster poverty reduction in drought-prone Araucanía, the Chilean Irrigation Commission is planning an important expansion of irrigated areas. Scenarios incorporating climate change (2030–2059) were simulated for a pilot basin using the WEAP water allocation model, showing that larger irrigated areas, coupled with higher temperatures and less precipitation, are likely to cause severe seasonal water scarcity. As decision support for the planning of effective measures to increase drought resilience, we modelled the construction of two upstream reservoirs combined with higher irrigation efficiency. We find that unmet water demand can be reduced by up to 97.7% by these measures.

Water management in the high mountain watersheds of the Sierra Nevada National Park (southern Spain). An example of ancestral Integrated Water Management

Sierra Nevada is the main mountain range in the southern Iberian Peninsula and has been catalogued as a Biosphere Reserve (1986), a Natural Park (1989) and a National Park (1999). Apart from its ecological, geomorphological and landscape singularities, there are other remarkable hydrological, historical and cultural features, such as the ancestral water management performed at the headwaters of the rivers. A dense network channels excavated in the ground, the so-called acequias de careo, allows the derivation of melt water from of the river water head towards the higher zone of the hillsides, where it infiltrates. It slowly flows down through the weathered zone of the metamorphic rocks, until reaching the rivers and springs used for supply and irrigation. This water management system, implemented since the Muslim conquest of southern Spain (VIII century), has led to a remarkable transformation of the landscape, where agricultural terraces and pastures coexist with ecosystems of high ecological value. This paper describes the careos water-management technique in a pilot basin, the Bérchules watershed, recently studied during 2014 and 2015 by the Geological Survey of Spain. Migration, the abandonment of cultivated lands and, consequently, of the acequias de careo are affecting the dynamics of the rivers, endangering the delicate balance reached between man and nature in the Sierra Nevada, after many centuries of harmonious coexistence.

DNA damage detection by Comet Assay on Daphnia magna: Application in freshwater biomonitoring

Monitoring of water genotoxicity still remains underexploited in risk assessment. The present study aimed at standardizing and evaluating the sensitivity and applicability of the Comet Assay adapted for Daphnia magna in genotoxicological investigations in freshwater environments. Two sampling campaigns (2014–2015) were performed in the watercourses of a pilot basin located in the Parma district (Italy). Fourteen sampling stations with different Ecological Status and/or EBI values were selected, all with a good Chemical Status according to the EU–Water Framework Directive 2000/60. The Alkaline Comet Assay was performed on 48 h-aged daphnids exposed (24 h) to 23 water samples. In parallel, the acute toxicity test was carried out. Daphnids exposed to samples, collected upstream the main watercourses in non-impacted areas, showed low DNA migration (Tail Intensity percentage – TI% - in the range 2.97–13.21), similar to laboratory controls. An increase in genotoxicity (TI% in the range 20–40) proceeding from the mountain towards the plain area was observed, in agreement with the land uses and the ES/EBI values of the stations. The highest genotoxic damage was observed after exposure to samples from watercourses of the minor hydrographic network in the plain area and waterbodies receiving wastewater treatment plant outflows. A modified version of the Comet Assay able to identify the presence of genotoxins inducing DNA oxidative damage, after standardization, was applied to daphnids treated with waters from 4 selected monitoring stations. The presence of oxidative contaminants was detected downstream a wastewater treatment plant outflow.The Comet Assay on D. magna has proven to be sensitive and able to discriminate among differently impacted areas and might be applied routinely. The FPG-Comet proved to be able to highlight the presence of contaminants causing oxidative stress.In our knowledge, this is the first time that Comet Assay on Daphnia magna is successfully applied for freshwater monitoring.

The Recent Sediment Record as an Indicator of Past Soil-Erosion Dynamics. Study in Dehesa Areas in the Province of Cáceres (Spain)

The work presented is a study of the recent sediment deposits in a pilot basin in dehesa areas in the province of Cáceres (Spain) through analysis of the sediment record, radiocarbon dating and correlation with historic data to assess the factors that conditioned the deposit in these areas over time. It is a qualitative study based on the important role of sediments as recorders of history, given that sediment facies and their architecture provide one of the best records of past processes and environmental factors. For the study, sediment profile surveys were used to determine the configuration and characteristics of the infill and its chronology. The sediment model of the facies studied is associated with a context of slope water erosion that led to the infill of the watercourse areas, mainly sand and fine gravel, where alterations in the normal rate were detected due to the insertion of a thicker level of materials (soil stoniness) that was able to be dated. The sediment and chronological results obtained can be used to determine the historical events in the area that could have affected the erosion and deposit processes in the basin for the estimated period, from the late 18th to the early 19th century. During this period, pastureland that maintained the ecological balance of the dehesa, with a balanced, stable displacement of soil particles, was converted to cropland, in most cases resulting in soil with a limited profile, overuse and the consequent loss of structure and texture, making it more vulnerable to erosion. Greater remobilisation would have carried thicker material to the watercourses than the material deposited as a result of limited ploughing. This study provides data for the dehesa areas studied with regard to their hydrogeomorphological dynamics, from which past environmental impacts due to tillage can be inferred.

Evaluation of Multi-Precipitation Products for Multi-Time Scales and Spatial Distribution During 2007-2015

Recently, several precipitation products are released with the improved algorithm to strengthen the performance of precipitation construction and monitoring. These data play a key role in a wide range of hydrological models, water resources modeling and environmental researches. Especially in developing countries like Vietnam, it is challenging to gather data for long-term time series at scales of daily and sub-daily due to the very coarse density of observation station. In order to overcome the problem of data scarcity, this study aims to evaluate the performance of newest multiple precipitation products including Tropical Rainfall Measuring Mission (TRMM 3B42 V7), Climate Prediction Center (CPC) MORPHing Version 1.0 (CMORPH_V1.0), European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis systems (ERA-Interim), Climate Research Unit Time series Version 4.0.1 (CRU TS 4.0.1) and Asian Precipitation-Highly-Resolved Observational Data Integration Towards Evaluation of Water Resources version 2 (APHRODITE) in comparison with measured precipitation for multiple time scales (daily, monthly, seasonal and annual), taking the VuGia-ThuBon (VG-TB) as a pilot basin where climate regime is complex. Seven continuous and four dichotomous statistics are applied to evaluate the precipitation estimates qualitatively at multiple time scales. In addition, specifically, evaluation of spatial distribution of multiple time scales is implemented. The results show lower precipitation estimates in areas of high elevation and higher precipitation estimates over the areas of plain and coastal in comparison with measured precipitation for all considered precipitation data. More importantly, ERA-Interim well captures rain events of heavy rain (50.0-100 mm/day). CMORHPH_V1.0 better reproduces the rain events with little overestimation of light rain (0.6-6 mm/day) than the others. For zero rain events (0-0.6 mm/day), TRMM 3B42 V7 gives the best performance. Furthermore, the cumulative distribution function of APHRODITE well matches the distribution of measured precipitation. All precipitation products completely fail to capture the rain events of extremely heavy rain. More importantly, a formula is proposed to scale and adjust the merged satellite precipitation at a sub-daily scale.

A meta-heuristic approach for multivariate design flood quantile estimation incorporating historical information

Abstract Design flood quantiles are crucial for hydraulic structures design, water resources planning and management, whereas previous multivariate hydrological quantile estimation methods usually do not consider historical flood information. To overcome such limitations, a meta-heuristic inference function for margins (MHIFM) approach, coupling meta-heuristic algorithm with a modified inference function for margins (IFM) method, is developed for modeling the joint distributions of flood peak and volumes with incorporation of historical flood information. Then, the most likely realization (MLR) and equivalent frequency combination (EFC) methods are employed for selecting multivariate design floods on a quantile iso-surface. The Danjiangkou reservoir located in Hanjiang River basin, the first pilot basin of most regulated water resources management policy in China, is selected as a case study. Application results indicate that the MHIFM approach shows good performance for estimating the parameters of marginal and joint distributions; moreover, the MLR method yields safer design flood quantiles than the EFC method in terms of highest routed reservoir water levels. The proposed MHIFM approach associated with the MLR method is safer and more rational for reservoir design, which would provide rich information as the reference for flood risk assessment, reservoir operation and management.

A Proposal to Evaluate Drought Characteristics Using Multiple Climate Models for Multiple Timescales

This study presents a method to investigate meteorological drought characteristics using multiple climate models for multiple timescales under two representative concentration pathway (RCP) scenarios, RCP4.5 and RCP8.5, during 2021–2050. The methods of delta change factor, unequal weights, standardized precipitation index, Mann–Kendall and Sen’s slope are proposed and applied with the main purpose of reducing uncertainty in climate projections and detection of the projection trends in meteorological drought. Climate simulations of three regional climate models driven by four global climate models are used to estimate weights for each run on the basic of rank sum. The reliability is then assessed by comparing a weighted ensemble climate output with observations during 1989–2008. Timescales of 1, 3, 6, 9, 12, and 24 months are considered to calculate the standardized precipitation index, taking the Vu Gia-Thu Bon (VG-TB) as a pilot basin. The results show efficient precipitation simulations using unequal weights. In the same timescales, the occurrence of moderately wet events is smaller than that of moderately dry events under the RCP4.5 scenario during 2021–2050. Events classified as “extremely wet”, “extremely dry”, “very wet” and “severely dry” are expected to rarely occur under the RCP8.5 scenario.

Combining water supply and flood control purposes in the Coghinas Basin (Sardinia, Italy)

ABSTRACTThe increased level of impact on life and infrastructure and the environment caused by flooding in Sardinia (Italy) has resulted in the need for the Flood Risk Management Plans (FRMP). The FRMP has been developed by Sardinian Region Administration that selected the Coghinas Basin (North Sardinia) as a pilot basin in according with the EU and National legislation. Recently, the European Flood Directive 2007/60/CE has stated that the flood-risk evaluation should include a cost–benefit analysis and an integrated decision-making tool should help optimize operating rules for multipurpose reservoirs, primarily with regard to the mitigation of flood risks and high priority demand supplies, and selected flood control works. The main purpose of this study was to develop an integrated flood management model to predict flood inundation in the flood-prone areas for various probabilities of occurrence, identify the flood operating rules in a multipurpose reservoir which accomplish a reduction in flood risk, and assess the total damage due to flooding. The FRMP is currently assessing the impacts of new reservoir operating rules reservoir and new works for flood damage mitigation. Based on a calibrated benefit–cost analysis, the proposed model suggested the best scenario of reservoir operating rules and flood control works with a significant saving of money compared to the actual scenario in the FRMP.

Analysis of Hydrological Sensitivity for Flood Risk Assessment

In order for the Indian government to maximize Integrated Water Resource Management (IWRM), the Brahmaputra River has played an important role in the undertaking of the Pilot Basin Study (PBS) due to the Brahmaputra River’s annual regional flooding. The selected Kulsi River—a part of Brahmaputra sub-basin—experienced severe floods in 2007 and 2008. In this study, the Rainfall-Runoff-Inundation (RRI) hydrological model was used to simulate the recent historical flood in order to understand and improve the integrated flood risk management plan. The ultimate objective was to evaluate the sensitivity of hydrologic simulation using different Digital Elevation Model (DEM) resources, coupled with DEM smoothing techniques, with a particular focus on the comparison of river discharge and flood inundation extent. As a result, the sensitivity analysis showed that, among the input parameters, the RRI model is highly sensitive to Manning’s roughness coefficient values for flood plains, followed by the source of the DEM, and then soil depth. After optimizing its parameters, the simulated inundation extent showed that the smoothing filter was more influential than its simulated discharge at the outlet. Finally, the calibrated and validated RRI model simulations agreed well with the observed discharge and the Moderate Imaging Spectroradiometer (MODIS)-detected flood extents.

Pesticide contamination in groundwater bodies in the Júcar River European Union Pilot Basin (SE Spain).

The change from a traditional agricultural model to a modern, more productive one, coupled with population growth, has entailed an increased consumption of water, fertilizers and pesticides. This transformation has led to a greater risk of groundwater contamination. This study has analysed for this purpose a total of 314 samples (period 2010-2013). In addition, 332 samples from the Mancha Oriental groundwater body (period 2001-2003) were also examined in order to gain a better perspective on the temporal evolution of pesticides in groundwater bodies. Using this database, this study aims to characterize pesticide pollution and to examine possible processes. Triazine herbicides are the most common pesticides found and also appear in the highest concentrations, with terbuthylazine having a noteworthy concentration of 900ng/L. The irrigated agriculture and the physicochemical properties of pesticides are the most important factors influencing the concentration and type of pesticides that can reach groundwater. The spatial distribution of nitrate and pesticides do not correspond as they would if the two behaved similarly. Pesticides can completely biodegrade before reaching the saturated zone, but it is also possible that their degradation products have not been analysed and, therefore, their concentrations are underestimated.

Methods for Improvement of the Ecosystem Services of Soil by Sustainable Land Management in the Myjava River Basin

AbstractThe main aim of this study is the development of methods for the assessment of the ecosystem services (ESS) of soils within the RECARE project and the participatory identification of measures to combat soil threats caused by floods in the Myjava River basin. The Myjava Hills highlands are known for their rapid runoff response and related muddy floods, which are determined by both the natural and socio-economic conditions. Within the frame of the mentioned project, the ESS framework with detailed relationships between the ecology, societal response, driving forces and also human well-being was identified. Next, to assess the SLM practices in the pilot basin, the stakeholders, who showed an interest in solving the flood protection problems in their areas, took an active part in the process of evaluating, scoring and selecting the best sustainable land management practices (SLM) for the flood protection of soil. From the results which were proposed, the technology of vegetative strips was top rated within the total results among all the SLM measures in all the categories, followed by water-retaining ditches and small wooden dams. Building a polder least meets the proposed SLM criteria.

Hydrological modeling of a detention reservoir: flood control and aquifer recharge

ABSTRACT In this paper, we proposed studying a small urban drainage catchment, named Pilot Basin of Mirassol (PBM) in Natal, RN - Brazil whose outlet is a detention and infiltration reservoir (DIR). The rainfall-runoff transformation processes, water accumulation in DIR and the process of infiltration and percolation in the soil profile until the free aquifer were modeled; and, from rainfall event observations, water levels in DIR, free aquifer water level measurements, and also, parameter values determination, it was able to calibrate and modeling these combined processes. The mathematical modeling was carried out from the use of a distributed rainfall-runoff model, and besides, we developed a model to simulate the soil percolation in an unsaturated porous media. Continuous simulation was run over a period of eighteen months in time intervals of one minute. The generated hydrographs were transformed into inlet volumes to the DIR and then, it was carried out water balance in these time intervals, considering infiltration and percolation of water in the soil profile. As a result, we obtain an evaluation on the storage water process in DIR as well as the infiltration of water, redistribution into the soil and the groundwater aquifer recharge, in continuous temporal simulation. We found that the DIR has good performance in order to storage storm water (floods) and contributing to the local aquifer recharge process.

Drought indicators-based integrated assessment of drought vulnerability: a case study of Bundelkhand droughts in central India

Decision makers face multifaceted challenge in characterizing drought climatology for appropriate water resources-related drought management strategies. This paper focuses on understanding and quantifying the drought vulnerability of Bearma basin in the Bundelkhand region of central India, which is one of the prominent climate extremes that the region is affected by frequently. Regular drought conditions have been prevailing in the region in the last decade with continuous drought from 2004 to 2007. An integrated approach using multiple indicators has been developed to spatially identify the vulnerable regions. The Bearma basin has been selected as a pilot basin to develop a methodology for integrated drought vulnerability assessment adopting spatially and temporally varying drought characteristics represented by drought indicators. The temporally varying indicators include standardized precipitation index (SPI), surface water drought index and groundwater drought index. The spatial information of the indicators was categorized in layers prepared in the spatial domain using a geographic information system, and integrated values of weights of various indicators have been computed on a 50 × 50 m grid scale. The SPI has been applied to quantify monthly precipitation deficit anomalies on multiple time scales (1, 3, 6 and 12 months). The drought characteristics including frequency, duration and intensity and magnitude have been calculated with the estimated SPI. The multiple indicator approach has been used for arriving at the drought vulnerable zones. The highly vulnerable areas are located in the southern and northern regions of the Bearma basin. It has been observed that more than 26 % of the basin lies in the highly and critically vulnerable classes and consequently has greater drought-related negative impacts. Results show that the proposed method is highly effective in representing assessments of drought vulnerability.