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 JWARP  Vol.8 No.11 , October 2016
Management of Water Supply Reservoirs under Uncertainties in Arid and Urbanized Environments
Abstract: Simulation and evaluation study of the three Water Supply Reservoirs in the Notwane Catchment was undertaken using a hybrid modelling approach linking the reservoir simulation model (HEC-ResSim) model and a reservoir reliability analysis (RRA) model. It was used to understand the management challenges and operation aspects facing the recent failure and declining water supply from three reservoirs in Gaborone and the surrounding areas, a typical arid and urbanized environment where current and future water supply reliability is challenged by both climate and anthropologic factors. The model was analysed for a calibration period of ten years (1993-2002), and verification period of eight years (2003-2010) and then simulation period of 40 years (2011-2050). The simulation period up to the year 2050 was considered to include the year 2035, which is the planning horizon of the National Water Master Plan. The model calibration and verification results are satisfactorily accepted for the fit of the daily water levels. The values of R2 and the Nash-Sutcliffe model efficiency criteria for the calibration period, are 0.81/60%, 0.62/27% and 0.54/39% for the Bokaa dam, Gaborone dam and Nnywane dam, respectively. Various scenarios were considered to determine the plausible sources of uncertainty and challenge for operation and management of the water supply reservoirs considering: population and urbanization, sedimentation, seepage, climate change, operational aspects, among others. From the RRA model, it was found that Gaborone dam, which is the largest of the three dams has lower resilience, lower reliability and higher vulnerability associated with increasing population pressures, urbanisation and climatic factors. Climate change, sedimentation, seepage, operational rules, contributing to the operation and management of the dams could have accelerated the drying up of the reservoirs and the prevailing water supply situation, which might continue to be the future possible challenges of water supply in the area.
Cite this paper: Alemaw, B. , Keaitse, E. and Chaoka, T. (2016) Management of Water Supply Reservoirs under Uncertainties in Arid and Urbanized Environments. Journal of Water Resource and Protection, 8, 990-1009. doi: 10.4236/jwarp.2016.811080.
References

[1]   CSO (2009) Botswana Water Statistics, Population Census of Botswana. Central Statistics Office, Gaborone.

[2]   Guo, S., Chen, J., Li, Y., Liu, P. and Li, T. (2011) Joint Operation of the Multi-Reservoir System of the Three Gorges and the Qingjiang Cascade Reservoirs. Energies, 4, 1036-1050.
http://dx.doi.org/10.3390/en4071036

[3]   Loucks, D.P., Stedinger, J.R. and Haith, D.A. (1981) Water Resource Systems Planning and Analysis. Prentice Hall, Englewood Cliffs.

[4]   Simonovic, S.P. (1992) Reservoir Systems Analysis: Closing Gap between Theory and Practice. Journal of Water Resources Planning and Management, 118, 262-280.
http://dx.doi.org/10.1061/(ASCE)0733-9496(1992)118:3(262)

[5]   Wurbs, R.A. (2012) Generalized Models of River System Development and Management. Texas Water Journal, 3, 26-24.

[6]   Labadie, J. (1997) Reservoir System Optimization Models. Water Resources Update, University Council on Water Resources No. 108, Summer, 83-110.

[7]   WUC (2015) Dam Levels and Water Supply Situation.
http://www.wuc.bw/wuc-content.php?cid=109

[8]   HEC (1981) HEC-3: Reservoir System Analysis for Conservation User’s Manual. US Army Corps of Engineers, Institute for Water Resources, Hydrologic Engineering Center, Davis.

[9]   HEC (1989) HEC-5: Simulation of Flood Control and Conservation Systems. US Army Corps of Engineers, Institute for Water Resources, Hydrologic Engineering Center, Davis.

[10]   HEC (2003) HEC-ResSim, Reservoir System Simulation User’s Manual, Version 2.0. US Army Corps of Engineers, Institute for Water Resources, Hydrologic Engineering Center, Davis.

[11]   HEC (2007) HEC-ResSim, Reservoir System Simulation User’s Manual, Version 3.0. US Army Corps of Engineers, Institute for Water Resources, Hydrologic Engineering Center, Davis.

[12]   HEC (2013) HEC-ResSim Reservoir System Simulation. User’s Manual. Version 3.1. US Army Corps of Engineers, Hydrologic Engineering Center.

[13]   Hashimoto, T., Loucks, D.P. and Stedinger, J. (1982) Reliability, Resilience and Vulnerability for Water Resources System Performance Evaluation. Water Resources Research, 18, 14-20.
http://dx.doi.org/10.1029/WR018i001p00014

[14]   Loucks, D.P. (1997) Quantifying Trends in System Sustainability. Hydrological Sciences Journal, 42, 513-530.
http://dx.doi.org/10.1080/02626669709492051

[15]   Zongxue, X., Jinno, K., Kawanura, A., Takesaki, S. and Ito, K. (1998) Performance Risk Analysis for Fukuoka Water Supply System. Water Resources Management, 12, 13-30.
http://dx.doi.org/10.1023/A:1007951806144

[16]   Allen, R.G., Pereira, L.S., Raes, D. and Smith, M. (1998) FAO Irrigation and Drainage Paper NO. (56 1998) Crop Evapotranspiration. Guidelines for Computing Crop Water Requirements, United Nations, Rome.

[17]   Box, G. and Jenkins, G. (1970) Time Series Analysis: Forecasting and Control. Holden-Day, San Francisco.

[18]   Hipel, K.W. and McLeod, A.I. (1994) Time Series Modelling of Water Resources and Environmental Systems. Elsevier, Amsterdam.

[19]   Zhang, G.P. (2003) Time Series Forecasting Using a Hybrid ARIMA and Neural Network Model. Neurocomputing, 50, 159-175.
http://dx.doi.org/10.1016/S0925-2312(01)00702-0

[20]   Parida, B.P., Moalafhi, D.B. and Kenabatho, P.K. (2006) Forecasting Runoff Coefficients Using ANN for Water Resources Management: The Case of Notwane Catchment in Eastern Botswana. Physics and Chemistry of the Earth, 31, 928-934.
http://dx.doi.org/10.1016/j.pce.2006.08.017

[21]   Parida, B.P., Moalafhi, D.B. and Kenabatho, P.K. (2006) Forecasting Runoff Coefficients Using ANN for Water Resources Management: The Case of Notwane Catchment in Eastern Botswana. Physics and Chemistry of the Earth, 31, 928-934.
http://dx.doi.org/10.1016/j.pce.2006.08.017

[22]   Moalafhi, D.B., Parida, B.P. and Kenabatho, P.K. (2014) A Hybrid Stochastic-ANN Approach for Flow Partitioning in the Okavango Delta of Botswana. Global NEST Journal, 16, 68-79.

[23]   FAO (2014) How to Calculate Water Losses Caused by Seepage.
ftp://ftp.fao.org/fi/CDrom/FAO_Training/FAO_Training/General/x6705e/x6705e02.htm

[24]   DWA (Department of Water Affairs) (2004) A Policy for Achieving a Water-Wise and Water-Efficient Botswana. Draft Water Conservation Policy, July 2004. Gaborone.

[25]   National Water Master Plan Review, SMEC and EHES (2006) Water Development Modelling, Vol. 11, Department of Water Affairs, Ministry of Mineral, Energy and Water Resources, Gaborone.

[26]   National Geographic (2015) Why Did LA Drop 96 Million “Shade Balls” into Its Water?
http://news.nationalgeographic.com/2015/08/150812-shade-balls-los-angeles-California-drought-w
ater-environment/


 
 
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