Characterizing the Water Balance of the Sooke Reservoir, British Columbia over the Last Century

Climate

Arelia T. Werner²  Terry D. Prowse³  Barrie R. Bonsal¹ 

[1] Environment Canada, 11 Innovation Boulevard, Saskatoon, Saskatchewan, S7N 3H5, Canada; E-Mail:;Pacific Climate Impacts Consortium, University of Victoria, Victoria, BC V8P 5C2, Canada;Water and Climate Impacts Research Centre, Department of Geography, Environment Canada at the University of Victoria, Victoria, British Columbia, V8W 3R4, Canada; E-Mail:

关键词: water balance;    evaporation;    climate trends;    Mediterranean climate;    Sooke Reservoir;    SPEI;    SPI;   

DOI  :  10.3390/cli3010241

来源: mdpi

【 摘 要 】

Infrastructure such as dams and reservoirs are critical water-supply features in several regions of the world. However, ongoing population growth, increased demand and climate variability/change necessitate the better understanding of these systems, particularly in terms of their long-term trends. The Sooke Reservoir (SR) of British Columbia, Canada is one such reservoir that currently supplies water to ~300,000 people, and is subject to considerable inter and intra-annual climatic variations. The main objectives of this study are to better understand the characteristics of the SR through an in-depth assessment of the contemporary water balance when the basin was intensively monitored (1996–2005), to use standardized runoff to select the best timescale to compute the Standard Precipitation (SPI) and Standard Precipitation Evaporation Indices (SPEI) to estimate trends in water availability over 1919 to 2005. Estimates of runoff and evaporation were validated by comparing simulated change in storage, computed by adding inputs and subtracting outputs from the known water levels by month, to observed change in storage. Water balance closure was within ±11% of the monthly change in storage on average when excluding months with spill pre-2002. The highest evaporation, dry season (1998) and lowest precipitation, wet season (2000/2001) from the intensively monitored period were used to construct a worst-case scenario to determine the resilience of the SR to drought. Under such conditions, the SR could support Greater Victoria until the start of the third wet season. The SPEI and SPI computed on a three-month timescale had the highest correlation with the standardized runoff, R² equaled 0.93 and 0.90, respectively. A trend toward drier conditions was shown by SPEI over 1919 to 2005, while moistening over the same period was shown by SPI, although trends were small in magnitude. This study contributes a validated application of SPI and SPEI, giving more credit to their trends and estimated changes in drought.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.