scholarly journals A Multi-Reservoir Study of the Impact of Uncertainty in Pool Evaporation Estimates on Water-Availability Models

Author(s):  
R.C. Phillips ◽  
Nigel Kaye ◽  
John Saylor

Quantifying evaporative loss from reservoirs plays a critical role in sound water-availability management plans and in reservoir management. Various methods are used to quantify reservoir evaporation; however, each method carries a degree of uncertainty that propagates to model predictions of available water within a reservoir or a reservoir network. Herein, we explore the impact of uncertainty in reservoir evaporation on model outputs of historical and future water availability throughout the five major reservoirs in the Savannah River Basin in South Carolina, USA, using four different evaporation methods. Variability in the total available water is evaluated using the United States Army Corps of Engineers (USACE) 2006 Drought Contingency Plan hydrologic model of the Savannah River Basin, which incorporates recent water-management plans and reservoir controls. Results indicate that, during droughts, reservoir evaporation plays a large role in water-availability predictions, and uncertainty in evaporative losses produces significant uncertainty in modeled water availability for extreme events. For example, the return period for an event in which the availability of water in Lake Hartwell was reduced to 50% of full pool capacity varied from 38.2 years to 53.4 years, depending on the choice of evaporation parameterization. This is a variation of 40% in the return period, depending on the choice of evaporation method.

Author(s):  
Sarfaraz Alam ◽  
Md. Mostafa Ali ◽  
Ahmmed Zulfiqar Rahaman ◽  
Zahidul Islam

Abstract The streamflow of Brahmaputra River Basin is vital for sustainable socioeconomic development of the Ganges delta. Frequent floods and droughts in the past decades indicate the susceptibility of the region to climate variability. Although there are multiple studies investigating the basin's future water availability, most of those are based on limited climate change scenarios despite the wide range of uncertainties in different climate model projections. This study aims to provide a better estimation of projected future streamflow for a combination of 18 climate change scenarios. We develop a hydrologic model of the basin and simulate the future water availability based on these climate change scenarios. Our results show that the simulated mean annual, mean seasonal and annual maximum streamflow of the basin is expected to increase in future. By the end of the 21st century, the projected increase in mean annual, mean dry season, mean wet season, and annual maximum streamflow is about 25, 178, 11, and 22%, respectively. We also demonstrate that this projected streamflow can be expressed as a multivariate linear regression of projected changes in temperature and precipitation in the basin and would be very useful for policy makers to make informed decision regarding climate change adaptation.


Nativa ◽  
2019 ◽  
Vol 7 (6) ◽  
pp. 718
Author(s):  
Rafael Alexandre Sá ◽  
Marcos Koiti Kondo ◽  
Edson De Oliveira Vieira ◽  
Silvânio Rodrigues Dos Santos ◽  
Nayara Paula Andrade Vieira ◽  
...  

A simulação hidrológica de bacias hidrográficas tem se tornado uma ferramenta importante de planejamento e gestão de recursos hídricos, projetando-se inclusive a disponibilidade hídrica a partir das mudanças climáticas. Dessa forma, objetivou-se avaliar a eficiência do modelo hidrológico SWAT na simulação da vazão da bacia hidrográfica do rio Riachão, no Norte de Minas Gerais, sob impacto de cenários alternativos de elevação da temperatura média do ar. O modelo SWAT foi ajustado para o período de 01/01/2008 a 31/12/2014 e calibrado com os dados das vazões hidrometradas obtendo valores do coeficiente de eficiência Nash-Sutcliffe (NSE) de 0,74 e 0,79 e tendência percentual (PBIAS) 15,45% e 16,72%, nas fases de calibração e validação, respectivamente. A disponibilidade de água superficial da bacia hidrográfica para comparação dos cenários foi calculada por meio da curva de permanência da vazão de referência Q90, obtendo-se o valor de 0,081 m3 s-1 para o modelo calibrado. Os cenários de aumento da temperatura média da bacia em 1,5; 2,0; 3,0; 4,0 e 5,0 °C levaram ao decréscimo da Q90 em 7,66; 8,98; 10,49; 14,06 e 17,76%, respectivamente.Palavras-chave: escoamento superficial; modelo SWAT; cenários climáticos; gerenciamento de recursos hídricos. HYDROLOGICAL SIMULATION TOOL FOR MANAGEMENT OF WATER RESOURCES IN THE FUNCTION OF CLIMATE CHANGE IN THE RIACHÃO RIVER BASIN, MG, BRAZIL ABSTRACT: The hydrological simulation of watersheds becomes a major tool for planning and management of water resources, including water availability prediction from global climate change. Thus, the objective was to evaluate the efficiency of the SWAT hydrologic model to simulate the stream flow of Riachão river basin, North of Minas Gerais State, Brazil, under the impact of alternative scenarios with the increase in mean surface air temperature. The SWAT model was adjusted for 1/1/2008 to 12/31/2014 period and calibrated with data measurement obtaining values the Nash-Sutcliffe efficiency (NSE) of 0.74 and 0.79 and percent bias (PBIAS) of 15.45 and 16.72% was found to calibration and validation period, respectively. The surface water availability in the hydrographic basin was calculated by Q90 streamflow, with calibrated value of 0.081 m³s-1. The scenarios of increase in mean air temperature (1.5, 2.0, 3.0, 4.0 and 5.0 ºC) reduced Q90 by 7.66, 8.98, 10.49, 14.06 and 17.76%, respectively.Keywords: runoff; SWAT model; climate scenarios; water resource management.


2012 ◽  
pp. 149-152
Author(s):  
János Fehér

In the European Region agriculture is the second largest water user after power industry cooling water use. As part of the implementation of Water Framework Directive EU Member States prepared their river basin management plans by the end of 2009 or first half of 2010, In these plans impacts of agriculture on water bodies have received attention. The detailed information elaborated in the plans by countries and river basin districts were uploaded into the WFD section of the WISE system. This database provides opportunity for multi-criteria analysis for different water types. The paper discusses the effects of agriculture on hydromorphological pressures and impacts affecting surface water bodies. It was pointed out that among the pressures affecting European surface water bodies the hydromorphological and diffuse pressures represent the highest ratios (Figure 1). Within the hydromorphological pressures affecting classified surface water bodies the ratio of pressures related to agricultural activities is low,it does not exceed 1% at European level. In case of Hungary the agriculture related river management pressures effect about 80% of the surface water bodies, which is much higher than the corresponding European average. The agricultural water abstractions affect about 10% of the Hungarian surface water bodies (Figures 2 and 3). The river and lake water bodies are impacted in significant ratio by nutrient enrichments and organic material enrichments, while in case of river water bodies the impact of organic material enrichments is also significant (Figures 4 and 5).


2018 ◽  
Vol 38 (1) ◽  
pp. 105-114 ◽  
Author(s):  
Gloria C. Okafor ◽  
Kingsley N. Ogbu

AbstractChanges in runoff trends have caused severe water shortages and ecological problems in agriculture and human well-being in Nigeria. Understanding the long-term (inter-annual to decadal) variations of water availability in river basins is paramount for water resources management and climate change adaptation. Climate change in Northern Nigeria could lead to change of the hydrological cycle and water availability. Moreover, the linkage between climatic changes and streamflow fluctuations is poorly documented in this area. Therefore, this study examined temporal trends in rainfall, temperature and runoff records of Kaduna River basin. Using appropriate statistical tools and participatory survey, trends in streamflow and their linkages with the climate indices were explored to determine their amplifying impacts on water availability and impacts on livelihoods downstream the basin. Analysis indicate variable rainfall trend with significant wet and dry periods. Unlike rainfall, temperature showed annual and seasonal scale statistically increasing trend. Runoff exhibit increasing tendency but only statistically significant on annual scale as investigated with Mann–Kendall trend test. Sen’s estimator values stood in agreement with Mann–Kendall test for all variables. Kendall tau and partial correlation results revealed the influence of climatic variables on runoff. Based on the survey, some of the hydrological implications and current water stress conditions of these fluctuations for the downstream inhabitants were itemized. With increasing risk of climate change and demand for water, we therefore recommend developing adaptive measures in seasonal regime of water availability and future work on modelling of the diverse hydrological characteristics of the entire basin.


1983 ◽  
Vol 5 (2) ◽  
pp. 6-7
Author(s):  
Susan Duda

In 1974 Public Law 93-251 authorized the estaablishment of the Big South Fork National River and Recreation Area (BSFNRRA). Included were approximately 125,000 acres of portions of a five county area in southeastern Kentucky and north central Tennessee consisting of the Big South Fork River, its tributaries, gorge, and adjacent rim area. Original plans called for the gorge area to remain in its undeveloped state and for the rim area to be developed with lodges, campgrounds, overlooks, trails, and picnic areas. The acquisition of land and the design and construction of roads and facilities were among the responsibilities of the United States Army Corps of Engineers, with the National Park Service assuming responsibility for management once the BSFNRRA is officially established.


2018 ◽  
Vol 22 (1) ◽  
pp. 709-725 ◽  
Author(s):  
Katrina E. Bennett ◽  
Theodore J. Bohn ◽  
Kurt Solander ◽  
Nathan G. McDowell ◽  
Chonggang Xu ◽  
...  

Abstract. Accelerated climate change and associated forest disturbances in the southwestern USA are anticipated to have substantial impacts on regional water resources. Few studies have quantified the impact of both climate change and land cover disturbances on water balances on the basin scale, and none on the regional scale. In this work, we evaluate the impacts of forest disturbances and climate change on a headwater basin to the Colorado River, the San Juan River watershed, using a robustly calibrated (Nash–Sutcliffe efficiency 0.76) hydrologic model run with updated formulations that improve estimates of evapotranspiration for semi-arid regions. Our results show that future disturbances will have a substantial impact on streamflow with implications for water resource management. Our findings are in contradiction with conventional thinking that forest disturbances reduce evapotranspiration and increase streamflow. In this study, annual average regional streamflow under the coupled climate–disturbance scenarios is at least 6–11 % lower than those scenarios accounting for climate change alone; for forested zones of the San Juan River basin, streamflow is 15–21 % lower. The monthly signals of altered streamflow point to an emergent streamflow pattern related to changes in forests of the disturbed systems. Exacerbated reductions of mean and low flows under disturbance scenarios indicate a high risk of low water availability for forested headwater systems of the Colorado River basin. These findings also indicate that explicit representation of land cover disturbances is required in modeling efforts that consider the impact of climate change on water resources.


Water ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 233
Author(s):  
Elia M. Tapia-Villaseñor ◽  
Eylon Shamir ◽  
Mary-Belle Cruz-Ayala ◽  
Sharon B. Megdal

The impact of climate uncertainties is already evident in the border communities of the United States and Mexico. This semi-arid to arid border region has faced increased vulnerability to water scarcity, propelled by droughts, warming atmosphere, population growth, ecosystem sensitivity, and institutional asymmetries between the two countries. In this study, we assessed the annual water withdrawal, which is essential for maintaining long-term sustainable conditions in the Santa Cruz River Aquifer in Mexico, which is part of the U.S.–Mexico Transboundary Santa Cruz Aquifer. For this assessment, we developed a water balance model that accounts for the water fluxes into and out of the aquifer’s basin. A central component of this model is a hydrologic model that uses precipitation and evapotranspiration demand as input to simulate the streamflow into and out of the basin, natural recharge, soil moisture, and actual evapotranspiration. Based on the precipitation record for the period 1954–2020, we found that the amount of groundwater withdrawal that maintains sustainable conditions is 23.3 MCM/year. However, the record is clearly divided into two periods: a wet period, 1965–1993, in which the cumulative surplus in the basin reached ~380 MCM by 1993, and a dry period, 1994–2020, in which the cumulative surplus had been completely depleted. Looking at a balanced annual groundwater withdrawal for a moving average of 20-year intervals, we found the sustainable groundwater withdrawal to decline from a maximum of 36.4 MCM/year in 1993 to less than 8 MCM/year in 2020. This study underscores the urgency for adjusted water resources management that considers the large inter-annual climate variability in the region.


Teras Jurnal ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 165
Author(s):  
Asril Zevri

<p><em>Sei Sikambing River Basin is one of the Sub Das of Deli River which has an important role in water requirement in Medan City. Rainfall with high intensity is supported by changes in land use causing floods which reach 0.6 m to 1 m from river banks. The purpose of this study was to map the Sei Kambing River basin flood inundation area as information to the public in disaster mitigation efforts. The scope of this research is to analyze the maximum daily rainfall with a return period of 2 to 100 years, analyze flood discharge with a return period of 2 to 100, analyze flood water levels with HECRAS software, and spatially map flood inundation areas with GIS. The results showed that the return flood rate of the Sikambing watershed with a 25-year return period of 211.94 m<sup>3</sup>/s caused the flood level of the Sikambing watershed to be between 1.7 m to 3.7 m. The Sikambing watershed flood inundation area reached an area of 1.19 Km<sup>2</sup> which resulted in the impact of flooding on 5 sub-districts in Medan, namely Medan Selayang District, Medan Sunggal, Medan Petisah, Medan Helvetia, and West Medan.</em><em></em></p>


Water ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 2516
Author(s):  
Yoonji Kim ◽  
Jieun Yu ◽  
Kyungil Lee ◽  
Hye In Chung ◽  
Hyun Chan Sung ◽  
...  

Highly concentrated precipitation during the rainy season poses challenges to the South Korean water resources management in efficiently storing and redistributing water resources. Under the new climate regime, water resources management is likely to become more challenging with regards to water-related disaster risk and deterioration of water quality. To alleviate such issues by adjusting management plans, this study examined the impact of climate change on the streamflow in the Bocheongcheon basin of the Geumgang river. A globally accepted hydrologic model, the HEC-HMS model, was chosen for the simulation. By the calibration and the validation processes, the model performance was evaluated to range between “satisfactory” and “very good”. The calibrated model was then used to simulate the future streamflow over six decades from 2041 to 2100 under RCP4.5 and RCP8.5. The results indicated significant increase in the future streamflow of the study site in all months and seasons over the simulation period. Intensification of seasonal differences and fluctuations was projected under RCP 8.5, implying a challenge for water resources managers to secure stable sources of clean water and to prevent water-related disasters. The analysis of the simulation results was applied to suggest possible local adaptive water resources management policy.


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