Surface Water Availability Research Articles

System Dynamics Approach for Water Resources Management: A Case Study from the Souss-Massa Basin

In several areas, many social, economic, and physical subsystems interact around water resources. Integrated water management is applied to maximize economic and social welfare in an equitable manner without compromising the sustainability of vital ecosystems, mainly in hydrologic-stressed areas. The Souss-Massa basin, with its semi-arid climate, has a significant demand for agricultural, industrial, tourism, and domestic water. It constitutes a complex system where the lack of knowledge of all the interacting subsystems has led to a shortage of water in quantity and quality. The objective of this study is to investigate the interactions between supply and demand at different stages using a System Dynamics (SD) approach. The model developed promotes a holistic understanding of the interactions between the different problem indicators that operate in water resources management in order to support decision-making action and successfully manage water resources at the Souss-Massa basin scale. The chosen performance indicator is based on the achievement of a baseline sustainability index (SI) defined as the ratio of available water to supply water that should be higher than 20% to avoid a water stress situation. The multisource data were gathered from different government agencies for the period spanning between 2007 and 2020. The results showed that the current policies do not lead to sustainable water management. Groundwater withdrawals have increased considerably, from 747 Mm3 in 2007 to 4884 Mm3 in 2020. The balance between water supply and demand is only reached for three years, 2010, 2015, and 2018, without ever reaching an SI of 20%. The sensitivity analysis showed that the sustainability of water resources in the Souss-Massa basin is mainly impacted by the availability of surface water, irrigated areas, and irrigation efficiency. This study will be of great interest to policymakers to provide optimal and sustainable water management strategies based on improved water use efficiency, and to contribute to the sustainable development agenda in arid and semi-arid regions.

Water availability and seasonality shape elemental stoichiometry across space and time.

The interaction of climate change and increasing anthropogenic water withdrawals is anticipated to alter surface water availability and the transport of carbon (C), nitrogen (N), and phosphorus (P) in river networks. But how changes to river flow will alter the balance, or stoichiometry, of these fluxes is unknown. The Lower Flint River Basin (LFRB) is part of an interstate watershed relied upon by several million people for diverse ecosystem services, including seasonal crop irrigation, municipal drinking water access, and public recreation. Recently, increased water demand compounded with intensified droughts have caused historically perennial streams in the LFRB to cease flowing, increasing ecosystem vulnerability. Our objectives were to quantify how riverine dissolved C: N: P varies spatially and seasonally and determine how monthly stoichiometric fluxes varied with overall water availability in a major tributary of LFRB. We used a long-term record (21-29 years) of solute water chemistry (dissolved organic carbon, nitrate/nitrite, ammonia, and soluble reactive phosphorus) paired with long-term stream discharge data across six sites within a single LFRB watershed. We found spatial and seasonal differences in soluble nutrient concentrations and stoichiometry attributable to groundwater connections, the presence of a major floodplain wetland, and flow conditions. Further, we showed that water availability, as indicated by the Palmer Drought Severity Index (PDSI), strongly predicted stoichiometry with generally lower C:N and C:P and higher N:P fluxes during periods of low water availability (PDSI < -4). These patterns suggest there may be long term and significant changes to stream ecosystem function as water availability is being dramatically altered by human demand with consequential impacts to solute transport, in-stream processing, and stoichiometric ratios. This article is protected by copyright. All rights reserved.

Impacts of Climate Change on Hydrological Regimes in the Congo River Basin

Surface water resources are essential for a wide range of human activities, such as municipal water supply, fishing, navigation, irrigation, and hydropower. Their regime is also linked to environmental sustainability, water-related risks, human health, and various ecosystem services. Global warming is expected to modify surface water availability, quality, and distribution and therefore affect water use productivity as well as the incidence of water-related risks. Thus, it is important for communities to plan and adapt to the potential impacts of climate change. The Congo River Basin, home to 75 million people, is subject to recurrent flood and drought events, which are expected to worsen as a result of climate change. This study aims to assess future modifications of the hydrological regime of the Congo River and the socio–economic impacts of these projected changes for three future periods: 2011–2041, 2041–2070, and 2071–2100. A Soil and Water Assessment Tool (SWAT) model of the Congo River Basin was developed, calibrated, and validated using daily rainfall observations combined with daily time series of precipitation, temperatures, relative humidity, solar radiation, and wind speed derived from the WFDEI (Watch Forced Era Interim) reanalysis data set. The outputs of ten Regional Climate Models (RCMs) from the Coordinated Downscaling Experiment (CORDEX-AFRICA) were statistically downscaled to obtain future climate time series, considering two Representative Concentration Pathways: RCP8.5 and RCP4.5. The calibrated model was used to assess changes in streamflow in all reaches of the Congo River. Results suggest relative changes ranging from −31.8% to +9.2% under RCP4.5 and from −42.5% to +55.5% under RCP 8.5. Larger relative changes occur in the most upstream reaches of the network. Results also point to an overall decrease in discharge in the center and southern parts of the basin and increases in the northwestern and southeastern parts of the basin under both emission scenarios, with RCP8.5 leading to the most severe changes. River discharge is likely to decrease significantly, with potential consequences for agriculture, hydropower production, and water availability for human and ecological systems.

The Use of Historical Data and Global Climate Models to Assess Historical and Future Surface Water and Groundwater Availability in the Trinity River Basin in Texas

This paper describes the results of a study that was done by the USGS to assess recent (2017) water availability, forecast long-term trends in water availability, assess changes in water availability, and forecast future water availability in the Trinity River Basin in Texas. The Trinity River Basin surface water model and Trinity River alluvium aquifer (TRAA) groundwater model were created to evaluate future conditions under different global climate models (GCM). The results of this study show minimal overall changes in water availability for both surface water and groundwater. Trend analyses using historical data (1900–2017) indicated an increase of annual precipitation on the watersheds that drain into the reservoirs in Regional Water Planning Group C. However, the Trinity River Basin surface water model GCM ensemble mean annual precipitation indicates a downward trend, resulting in a downward trend in surface runoff. Additionally, the GCM ensemble mean for the Trinity River Basin surface water model and the TRAA groundwater model both indicate a downward trend in recharge while the TRAA model GCM ensemble mean indicates an upward trend in the amount of groundwater leaving the aquifer to rivers and streams resulting in an upward trend of cumulative storage change.

Assessing Potential Habitat for Freshwater Mussels by Transferring a Habitat Suitability Model within the Ozark Ecoregion, Missouri

Habitat suitability models for freshwater mussels can inform conservation of these imperiled animals. Riverscape-scale hydrogeomorphic variables were previously used to predict suitable mussel habitat in the Meramec River basin, Missouri. We evaluated transferability of the Meramec River habitat suitability model to the Gasconade and Little Black rivers, in the Ozark Highlands ecoregion, Missouri. The best-fit models relied on transferring and adapting the original modeling framework to better represent the unique habitat characteristics of each river. Mussel bed occurrence in both rivers was associated with reaches that were classified as pools. Mussel beds in the Gasconade River were also associated with laterally stable reaches adjacent to small bluffs, distant from gravel bars, and with higher stream power indices. Mussel beds in the Little Black River were associated with reaches with higher surface water availability during low-flow conditions, lower stream power indices, and bluffs located downstream. Our results show that existing habitat models can be transferred to other streams with similar environmental conditions, but differences in watershed characteristics can affect transferability.

Estimating the spatio-temporal assessment of GRACE/GRACE-FO derived groundwater storage depletion and validation with in-situ water quality data (Yazd province, central Iran)

Due to the lack of surface water availability in Yazd province, groundwater has been overexploited as a key source of water supply, resulting in the overexploitation of groundwater resources for agricultural activities. This study employed the data of the Gravity Recovery and Climate Experiment (GRACE)/GRACE Follow-On (GFO) satellite to determine terrestrial water storage (TWS) and deriving groundwater storage (GWS) variations using global land data assimilation system (GLDAS) water storage components in Yazd province from 2003 to 2020. The time series results showed that the annual changes of GWS are positive from 2003 to 2007, and continue negative with a decrease in precipitation significantly causing depletion of GWS in the aquifers. The Pearson correlation coefficient is close to 0.58 between observed and GRACE-derived GWS on yearly basis and both show a decreasing GWS trend. The results of calculating the groundwater balance for aquifers showed that the renewable water resources have decreased from 786 to 250 million cubic meters (MCM) between the water year 2009–2010 and 2019–2020. This has caused the electrical conductivity (EC) to increase from about 8500 to 12,500 μS/cm. The correlation coefficient between EC and observed and GRACE-derived GWS was around −0.50 and −0.79, respectively. GRACE-derived and analytically calculated groundwater storage deficit (GSD) is around 2491 and 2775 MCM showing a similar downward trend. These results, while confirming GRACE-derived GWS, point out the need to revise the analytical calculation of the groundwater balance based on the unmodified aquifer domains and the non-uniform distribution of observation wells in most aquifers to reduce the difference between observed and GRACE-derived GWS anomalies.

The Dynamic Model of Water Balance in A Sub-Basin

Management of water resources in a river basin requires a new approach. The availability of water is a basic thing that must be considered given the increasing need for water. This study aimed to develop a water balance model in the Upper Bekasi River Sub Basin. In this study water balance model of the Bekasi River Sub Basin was built with several variables that affect water demand and availability, namely population growth rate, public facilities, and efforts to utilize resources. In this research, water supply and demand modelling was carried out using a dynamic system supported by Vensim software. Simulations were carried out from 2012 to 2045. The increase in population growth was directly proportional to the increased in population water needs. This dynamic model simulation used the application of rainwater harvesting and water-saving behaviour. Water demand for the Bekasi River Sub Basin was equal to 156.649.000 m3/year. The availability of surface water was 138.127.680 m3/year and had not been able to meet the water needs. The dynamic model showed that the water balance will be deficit in 2031, namely 51.883.200 m3/year. However, with the application of the water saving scenario, the water balance has a surplus of 258.564.000 m3 / year until the end of the simulation. Water reducing behavior can be used as an efficient method of water utilization. Keywords: Population, Rainwater harvesting, Simulation, Water management, Water resource

Interactions between Soil Moisture and Water Availability over the Inner Mongolia Section of the Yellow River Basin, China

The ecological conservation and high-quality development of the Yellow River Basin (YRB) has been declared as a major national strategy of China. Surface water availability (precipitation minus evapotranspiration, PME) poses challenges to the sustainability of ecosystems of the YRB. Noteworthy is that the Mongolian section of the YRB (IMYRB) is a critical ecological barrier in Northern China. Soil moisture (SM) changes are highly sensitive to PME and important for regional ecological security. However, SM vs. PME interactions and relevant mechanisms within the IMYRB are poorly understood. We found significant decreases in SM and PME over the east IMYRB (r = 0.7, p &lt; 0.05). During the wet (July, August, and September) and dry (April, May, and June) seasons, as well as the whole year, decreased SM drives increased PME through land-atmosphere interactions over more than 90% of the IMYRB. Reduction in SM decreased evapotranspiration over more than 80% of the IMYRB, increased surface temperature across more than 79% of the IMYRB, boosted atmospheric vertical ascent over more than 75% of the IMYRB, and enhanced moisture convergence and PME. This study highlights the land-atmosphere interactions over the IMYRB, implicating basin-scale impacts of climatic changes on water resources.

Assessment of Available Water and Crop Water Requirements of Major Crops in Nagarjuna Sagar Right Canal Command Area, Andhra Pradesh, India

The mean water releases at head section of 11 years of Nagarjuna Sagar Jawahar right main Canal, Andhra Pradesh, India is found to be 128.13 TMC (3,627.71 MCM). The mean surface water availability was estimated as 2,229 MCM. For the efficient utilization of groundwater, the quality plays a major role in terms of selection of crop variety for sustainable agriculture. The ground water quantity of the command area available was estimated 1385 MCM and the mean annual conjunctive use of command area was 3,614 MCM (128 TMC).&#x0D; The crop water requirement for paddy, cotton, chilies, millet and pulses were estimated in the command area by using CROPWAT model. The crop water requirement for paddy in NSRC command area of Guntur district for black soils was 848.2 mm. The irrigation water requirement was 638.9 mm and for red soils, crop water requirement for paddy and irrigation water requirements were 848.2 mm and 624.5 mm respectively. Similarly, computed for all the crops and overall crop water demand for both (Guntur and Prakasam) districts of NSRC command area for different soils and different crops per annum was 4,456 MCM without considering cattle and domestic water use. Based on the research, it was concluded that the available water is not sufficient and it is suggested to choose alternative crops for bringing entire area into cultivation.

Assessment of Soil Erosion Hazards in Kambiti Subcatchment, Murang’a County, Kenya

Erosion is a global problem that destroys soil and adversely affects ecosystem productivity. Soil erosion generally involves many processes but the major activities involve particles being transported and deposited to another location. With an increasing population, soil erosion, water availability, energy production, and biodiversity loss are some of the most pressing environmental problems around the world. Erosion is a hazard associated with agriculture in tropical and semi-arid areas. Kambiti sub catchment is part of the upper Tana catchment. The upper Tana catchment includes 25% of Kenya gazette forest. A large area of land has been degraded, resulting in a drastic reduction in surface water availability during the dry season and poor-quality water during the wet season caused by high silt levels. The main objective of the study is to assess erosion hazards using RUSLE model in Kambiti sub catchment area, Murang’a County. The specific objectives of the study were to determine the effect of rainfall erosivity and soil erodibility factor in Kambiti Sub catchment area in Murang’a County, to determine effect of slope factor to soil loss in Kambiti Sub-catchment area in Murang’a County, to determine the effect of crop protection and management factor in Kambiti Sub catchment area in Murang’a County to soil loss and to determine the strategies for management of soil and water in Kambiti Sub catchment area in Murang’a County. Data was collected from the catchment and analyzed using arc Geographical Information System to obtain the specific parameters in the revised universal soil loss equation model. Interpolation method was used to determine the mean annual precipitation. The k factor is a function of soil texture. Shape file for geological structure for Kenya was obtained from Kenya Agriculture and livestock Research Organisation and analyzed by use of arc GIS to obtain soil erodibility factor. The slope factor was analyzed using digital elevation model from arc view. Digital elevation model was gotten from STRM download. The C factor was derived from Landsat imagery from sentinel of 30metres by 30 metres. It was further analysed by unsupervised classification from Arc GIS. The sentinel clip of Kambiti sub-catchment was joined with ground trothing observations. The results were useful in estimation of soil loss therefore profiling the areas prone to soil loss. Study findings indicated rain drop impact and runoff were primarily responsible for causing erosion in Kambiti sub catchment. Anthropogenic factors played an important role in amplifying the severity of the damage, such as persistent vegetative degradation and destruction of soil structure due to organic matter depletion and routine shallow tillage. In recent years, erosion control has been hampered by the occurrence of gaps in knowledge regarding the integrated nature of erosion processes, leading to land damage caused by rill and inter-rill erosion going unaddressed. Poor people and those lacking capital to invest in reclaiming land are the main causes of abandoning degraded land. Through strategic awareness campaigns and education, soil erosion will be assessed and the knowledge gap will be closed. Participation of farmers in land use decisions is inevitable as it ensures that people who utilize land resources are recognized as equal partners in identifying problems and designing solutions. It was also recommended that Identification and operationalization of alternative off-farm income.&#x0D;

Assessing climate change impacts on surface water availability using the WEAP model: A case study of the Buffalo river catchment, South Africa

Study regionThe Buffalo River (BR) catchment, KwaZulu-Natal, South Africa. Study focusDue to the vast majority of the BR catchment’s water demands not being fully satisfied in recent years, studies investigating potential climate change impacts on the catchment's water supply availability are needed. The study’s objective was to therefore assess climate change-induced surface water availability (SWA) variations in the BR catchment from 2020 to 2100. To achieve this, the hydrologic Water Evaluation and Planning model was forced with the catchment's physical and hydrological data, and projected climate data from an ensemble of GCMs under RCP4.5 and RCP8.5 scenarios from CMIP5. New hydrological insights for the regionThe study findings projected increased precipitation, especially in the far future (2070–2100) whereby mean annual precipitation increased by 5 % to 8286 Mm3/annum under the worst-case climate change scenario (RCP8.5). With evapotranspiration and water abstractions averaging 4500 Mm3/annum and 115 Mm3/annum, respectively, surface runoff and SWA increased by 8 % and 10 %, yielding averages of 3265 Mm3/annum and 287 Mm3/annum, respectively. Even with the increased SWA, unmet demands also increased by 113 % towards the end of the 21st century. As the study established that climate change might exacerbate the BR catchment's water supply system's insufficiency to meet growing demands, such findings present an opportunity for the integrated Water-Energy-Food nexus approach to be further utilised for formulating sustainable water management strategies.

Evaluation of metaheuristic optimization algorithms for optimal allocation of surface water and groundwater resources for crop production

Extensive variability in current climatic conditions necessitates the need for optimal planning of water resources to manage socio-economic and environmental requirements efficiently. The optimal allocation of surface water and groundwater is essential to maximize crop net return due to uncertainty in seasonal rainfall, groundwater, and surface water availability in each region. This study demonstrated a multi-objective model to maximize the crop net return and efficient management of water resources. The multi-objective model comprised three objective functions maximizing the crop net return, minimizing the water deficit, and maximizing the aquifer recharge. The model’s practicability was analyzed through the case study of the Pennar-Palar-Cauvery link canal command in India. Three meta-heuristic approaches, particle swarm optimization (PSO), genetic algorithm (GA), and marine predators algorithm (MPA), were employed to solve the presented model. And their performance was evaluated using hypervolume and coverage metrics, indicating MPA’s superiority in obtaining well-distributed Pareto-optimal solutions. Thus, decision-makers can choose the best feasible solution based on current resource availability and preferences. The model was executed considering different cropping area deviations (5–25%) in the existing cropping pattern and allowance of groundwater mining from 0% to 70%. The obtained cropping pattern utilizing MPA at 25% cropping deviation achieved an increased net return of 1327.05 million INR.

Analysis of the impacts of land use land cover change on streamflow and surface water availability in Awash Basin, Ethiopia

The current study analyzed the impact of Land Use Land Cover (LULC) change on streamflow and surface water availability in the Akaki catchment of the Awash Basin, Ethiopia. Soil and Water Assessment Tool (SWAT) and Climatic Water Balance (CWB) models were used. The SWAT model calibrated and validated the daily streamflow. The results indicated that from 1993 to 2016, built-up and barren land areas increased by 5.3% and 3.4%, respectively. The SWAT model over-simulated the peak flows and best simulated the medium and low flows. Based on the calibrated daily streamflow, the runoff was 236.01 mm and 272.59 mm under the 1993 and 2016 LULC scenarios. The total water yield of the catchment was 366.7 mm and 382.01 mm for the 1993 and 2016 LULC scenarios, respectively. The seasonal CWB of the catchment depicted decreasing trend except for the Tsedey (SON) season. Based on the current study’s findings, since LULC change enhanced surface runoff and total water yield in the catchment, proactive flood management is recommended to reduce the impact of the flood hazard on life and property.

The Early Holocene archaeology of Florida: geospatial approaches to understanding Bolen mobility

ABSTRACT Three of the most influential archaeological models in the southeastern US have argued that early foragers organized their lifeways via seasonal movement along major drainage basins; around access to raw material sources, crossing drainage basins; or around group foraging needs, following central place foraging models. We examine the distribution of Early Holocene Bolen sites in Florida in light of these models by combining Florida Master Site File data with avocational collection data and conducting spatial analyses. It is not clear to what extent the models are applicable to this low-relief area with comparatively ubiquitous toolstone, little data on seasonality, and rivers that likely were not flowing. Our analyses suggest that Bolen site distribution is highly patterned, with a few extremely large sites clustered around water sources and numerous single artifact finds in more remote areas. Our interpretation is that Bolen represents a population increase coincident with greater surface water availability that facilitated regular aggregations. The spacing of large sites indicates to us local-group territories, each of which had toolstone resources and reliable water. North Florida may present a more general organizing principle that applies throughout the Southeast: water, seasonal variation, and toolstone availability.

Changes in habitat suitability for wintering dabbling ducks during dry conditions in the Central Valley of California

AbstractIn arid and Mediterranean regions, landscape‐scale wetland conservation requires understanding how wildlife responds to dynamic freshwater availability and conservation actions to enhance wetland habitat. Taking advantage of Landsat satellite data and structured and community science bird survey data, we built species distribution models to describe how three duck species, the Northern Pintail (Anas acuta), Green‐winged Teal (Anas crecca), and Northern Shoveler (Anas clypeata), respond to freshwater supply and food resources on different flooded land cover types in the Central Valley of California. Specifically, our models compared duck habitat suitability between the wettest and driest conditions in each month from September through April. Using abundance‐weighted boosted regression trees, we created three sets of species occurrence models based on different covariates: (1) near real‐time (hereafter “real‐time”) covariates in which duck observations were matched to the water availability within the 16‐day window of a Landsat observation, (2) a combination of real‐time covariates and waterfowl food resource covariates describing annual corn and rice biomass and managed wetland moist soil seed yield estimates derived from Landsat data, and (3) long‐term average covariates—the most common approach to species distribution modeling—in which long‐term average surface water availability was used. We modeled the monthly occurrence of three duck species as a function of surface water availability, land cover type, road density, temperature, and bird data source. We found that dry conditions result in reduced habitat suitability, with the biggest reductions in November through January and in agricultural fields; in contrast, suitability of flooded wetland habitat was relatively robust to surface water availability. When models of habitat suitability based on long‐term average climate conditions were compared to models based on real‐time conditions, the highest long‐term suitability values occurred in areas where suitability was high regardless of whether it was a wet or a dry year. While all models performed well, the inclusion of crop and wetland plant yield covariates resulted in slightly higher model performance. Overall, species distribution models created using data on the environmental conditions present at the time of bird observations can aid conservation efforts under extreme conditions over large spatial scales.

Salinification of Coastal Wetlands and Freshwater Management to Support Resilience

Climates are rapidly changing in wetland ecosystems around the world and historical land-use change is not always given enough consideration in climate adaptation discussions. Historical changes to hydrology and other key environments can exacerbate vegetation stress; e.g., recent drought and flood episodes are likely more extreme because of climate change. The contributions of global and regional changes that affect groundwater and surface water availability all need consideration in conservation planning including sea-level rise, coastal subsidence and compaction, fluid extraction, and floodplain reengineering. Where subsidence is not too extreme, healthy coastal vegetation often can keep ahead of sea-level rise by accreting elevation through sedimentary and/or biogenic processes. Better water conservation and minimum water delivery during drought may support foundational species and avoid wetland collapse. Local approaches have been developed to rewet inland floodplains decades after their reengineering for agricultural and urban development to support biodiversity in salinified coastal wetlands. The purpose of this paper is to describe inland wetland remediation techniques that may also be useful to increase freshwater delivery to coastal wetlands experiencing salinification. While some salinified coastal ecosystems may transition in the future, attempts can be made to remediate salinification related to historical land use in support of wetland conservation, health, and sustainability.

Surface Water Availability and Temperature (SWAT): An Innovative Index for Remote Sensing of Drought Observation

Surface Water Availability and Temperature (SWAT): An Innovative Index for Remote Sensing of Drought Observation

Water scarcity exacerbates feral ungulate use of ephemeral savanna waterholes in northern Australia

Context Australian savannas evolved in the absence of hooved mammals and are therefore prone to disturbance from exotic ungulates. Several ungulate species have established feral populations in Australia’s northern savannas. Because most ungulate species have high water requirements, seasonal and interannual changes in water availability are likely to affect their behaviour and the extent of their impacts on native ecosystems. However, few studies have investigated how water scarcity affects feral ungulate use of waterpoints in Australia. Aims The aim of this study was to determine whether seasonal and interannual water scarcity affected the visitation behaviours of feral pigs, cattle and water buffalo at ephemeral savanna waterholes within Limmen National Park, Northern Territory, Australia. Methods We used motion-triggered wildlife cameras to study feral ungulate visitation and behaviour at 20 waterholes. Generalised linear mixed-effects models were used to investigate whether the number of visits, duration of visits and number of individuals visiting waterholes varied with year and dry season progression. We also investigated whether these factors affected the amount of time ungulates spent foraging, drinking and wallowing at waterholes. Key results All three species visited waterholes more often, for longer periods and in larger numbers during a drought year compared with an average rainfall year. Cattle and buffalo spent more time drinking from waterholes during the drought, and pigs and cattle spent longer periods foraging. Buffalo also wallowed more during the drought. Responses to dry season progression varied among species. Cattle visited waterholes more frequently, for longer durations and in larger herd sizes as the dry season progressed, whereas buffalo use did not change. Pigs only increased their visitation to waterholes when water scarcity was most extreme, at the end of the dry season during the drought. Conclusions Our results demonstrate that water scarcity exacerbates feral ungulate use of savanna waterholes. Management and control programs for feral ungulates in Australian savannas may benefit from targeting different species under specific water scarcity conditions. Implications Because climate change is predicted to reduce surface water availability in northern Australia, feral ungulate use of savanna waterholes may intensify, risking further biodiversity losses and irreversible ecosystem damage.

Decadal Change in Ground Water Utilization Pattern in West Bengal, India

This research article is meant to highlight the topic present ground water utilization scenario of West Bengal, India. Contribution of irrigation structures for different minor irrigation censuses, irrigation potentiality, cropping pattern with the development of irrigation over time and the extent of use of ground water resources have included in the study. Secondary data on irrigation potentiality, cropping pattern, minor irrigation censuses over times has been assembled from Central Ground Water Board (CGWB) (Eastern Region), State water investigation directorate (SWID) and area on different crops is from the official statistics published time to time by public sources. In the study area, it has been found that utilizable water is much less than available water. The availability of surface water is more than groundwater. Gap between water demand and availability is more in southern districts of West Bengal. Per capita water available is decreasing as the population is increasing. In both the cases of culturable command area and gross irrigated area, irrigation through the surface water sources has shown negative growth rate.

Analysis of Surface Water Availability to Meet Agricultural Water Demands in Kediri Regency, Indonesia

This study aims to analyze the potential of surface water to meet agricultural water needs in Kediri Regency, Indonesia. Data from government agencies (i.e., Indonesian Bureau of Meteorology, Climatology, and Geophysics and Kediri Agriculture Office) and fieldwork were analyzed to achieve the research objectives. The data obtained consisted of rainfall, temperature, infiltration capacity, soil texture, root depth, and agricultural land area. The potential of surface water resources was calculated by using the Thornthwaite–Mather water balance method. The water balance results were compared with agricultural water demands, which were calculated on the basis of the area of agricultural land and type of crop, particularly paddy fields. Critical and noncritical conditions for surface water resources were classified on the basis of the ratio between the availability of surface water resources and the demand for agricultural water. Results showed that the total surface water potential widely varied by season. The water balance calculation indicated that all subwatersheds (SWs) experienced a water surplus in the rainy season, whereas almost all SWs were deficient in surface water in the dry season, Overall, the surface water in Kediri was critical in the rainy season and more severely critical in the dry season. The results of this study indicated that the high demand for agricultural water can affect the availability of water resources in the tropics. The results are expected to be considered in determining regional planning related to the use and need of water resources and supporting infrastructures.