Climate Change Water Resources Planning Impacts Incorporating Reservoir Surface Net Evaporation Fluxes: A Case Study

Abstract

The majority of p ublished studies on the im pacts of clim ate change on reservoired water resources system s have concentrated on the in¯uence of the clim atechange-m odi® ed in¯ow series. H owever, for reservoirs the direct net evaporation (i.e. evaporation less rainfall)¯uxes on the reservoir surface are also affected by clim ate change and, depending on the m agnitude of the change, could have signi® cant effects on the assessed impacts. In this study, we have performed reservoir storage-yield-reliability planning analyses on tw o m ultiple reservoir system s, one in England and the other in Iran, to investigate the possible effects of reservoir surface net evaporation¯ux for both baseline and clim ate-change conditions. The results showed that, under baseline conditions, consideration of net evaporation will require lower storages for the English system s and higher storages for the Iranian system s. The practical signi® cance of this is that English systems analysed without consideration of surface¯uxes represent an over-design which can provide a buffer against future shortages, whereas the under-design caused by ignoring surface¯uxes in the Iranian system s will exacerbate the problem of such shortages. Perturbing the baseline in¯ow and clim atological time-series data using a num ber of recently published clim ate-change scenarios produced different im pacts at high and low yields for both system s. Possible explanations are offered for these im pacts and suggestions are m ade for further studies.

Stable isotope ratios of tap water in the contiguous United States

“…[27] Surface reservoirs provide approximately 63% of all U.S. public supply water [Hutson et al, 2004], and monitoring and planning for the stability of these water sources represents a major challenge for water managers. Evaporative water loss from reservoirs can significantly impact water storage, and its effects on water resource stability, particularly under changing climatic conditions, can be difficult to incorporate in reservoir planning models [Adeloye et al, 1999;Montaseri and Adeloye, 2004]. Network-based stable isotope data provide a means of monitoring rates of water loss and regional water resource sensitivity to evaporation.…”

“…Evaporative water loss from reservoirs can significantly impact water storage, and its effects on water resource stability, particularly under changing climatic conditions, can be difficult to incorporate in reservoir planning models [Adeloye et al, 1999;Montaseri and Adeloye, 2004]. Network-based stable isotope data provide a means of monitoring rates of water loss and regional water resource sensitivity to evaporation.…”

Domestic Water Supply Dynamics Using Stable Isotopes <i>δ</i><sup>18</sup>O, <i>δ</i>D, and d-Excess

“…Adeloye et al [3] performed reservoir storage-yield-reliability planning analyses on two multiple reservoir systems, one in England and other in Iran, to investigate the possible effects of reservoir surface net flux from both baseline and climate-change conditions. The behavior of the two systems was different because of the great differences in climate (humid versus semi-arid).…”

“…The stability of water resources in regards to monitoring and planning represents a major challenge for water managers. The timing of precipitation and evaporative water loss from reservoirs can significantly affect water storage, proving difficulty in developing reservoir-planning models [3] [4]. In addition, changes in precipitation amounts, recharge rates, and land use can affect the residence time of water through watersheds altering reservoir storage capacity.…”

Water Balance Model of Lake Malawi and its Sensitivity to Climate Change

“…However, the direct net evaporation (i.e. evaporation less rainfall) fluxes on the lake surface are also affected by climate change and, depending on the magnitude of the change, could have significant effects on the assessed impacts [18]. In this study, a constant surface area was based on recommendations from previous studies [5,19].…”