Search

This paper focused on regional climate change impacts on hydro-meteorological variables in the Upper Chao Phraya River basin located in northern Thailand. The five global climate models were used with a number of 15 experiments to assess near future water resources over the period 2026-2040. The impacts of climate change were quantified in percentages relative to a retrospective period (1986- 2000). On average, the surface temperature tends to increase by 1.45, 1.48, and 1.80 °C under the lowest (RCP2.6), intermediate (RCP4.5), and highest (RCP8.5) CMIP5 greenhouse gas emission scenarios, respectively. Mathematical model called H08 was used, the coupling of three modules did a very good job on mimicking river discharge with high Nash-Sutcliffe and Index of Agreement. The projections of rainfall and its response to surface runoff and groundwater recharge exhibit relatively uneven distributions. The upper basin tends to face extremely heavy rainfall and taking place of serious flood, while the lower areas are expected to cope with drought. Based upon ensemble averages over the entire area, relative changes of -1.7% (-6.4%), -0.1% (-5.2%), and -2.0% (-9.3%) in the mean annual rainfall (groundwater recharge) are shown under the RCP2.6, RCP4.5, and RCP8.5 scenarios, respectively. This study included a groundwater recharge assessment indicating potential available groundwater use, which is considered to be a key resource for climate change adaptation. Based on these findings, implementing such an artificial groundwater recharge system is needed in order to harvest surplus water and making for coping with water stress in the dry season. [ABSTRACT FROM AUTHOR]

Assessing climate change risk to municipal water supplies is often conducted by hydrologic modeling specific to local watersheds and infrastructure to ensure that outputs are compatible with existing planning frameworks and processes. This study leverages the modeling capacity of an operational National Weather Service River Forecast Center to explore the potential impacts of future climate-driven hydrologic changes on factors important to planning at the Salt Lake City Department of Public Utilities (SLC). Hydrologic modeling results for the study area align with prior research in showing that temperature changes alone will lead to earlier runoff and reduced runoff volume. The sensitivity of average annual flow to temperature varies significantly between watersheds, averaging -3.8% °F-1 and ranging from 21.8% to 26.5% flow reduction per degree Fahrenheit of warming. The largest flow reductions occur during the high water demand months of May-September. Precipitation drives hydrologic response more strongly than temperature, with each 1% precipitation change producing an average 1.9% runoff change of the same sign. This paper explores the consequences of climate change for the reliability of SLC's water supply system using scenarios that include hydrologic changes in average conditions, severe drought scenarios, and future water demand test cases. The most significant water management impacts will be earlier and reduced runoff volume, which threaten the system's ability to maintain adequate streamflow and storage to meet late-summer water demands. [ABSTRACT FROM AUTHOR]