Humans and hydrology are the dynamic components of the arctic system. They closely interact and affect each other in many ways. Study of Human-Hydrological relationships is one key common interest for the NSF ARCSS and HARC programs. Recently, both programs have identified the Arctic Human-Hydrological Relationship as a major research gap, and both recommend more research efforts to characterize this relationship across sectors of human activity and Arctic regions. Currently this relationship has been explored in only a few cases that mainly investigate how Arctic hydrologic changes influence northern society and culture. It is, however, important to note that the study of human impacts on the arctic hydrologic system is also a great challenge and is a major research gap in the ARCSS programs. While various human activities -- such as water use for industry and irrigation, and change of land use and land cover -- affect hydrology regimes, construction and operation of large dams and reservoirs make the most significant changes in regional-global hydrology systems.
Many large dams and reservoirs have been constructed mainly for flood control and hydropower generation in the northern regions/watersheds, and their operation substantially alters river streamflow, sediment and thermal conditions. Large dams directly and significantly regulate streamflow; they change monthly and seasonal discharge regimes over space and time, and they affect yearly streamflow characteristics at the basin scale. It is important to note that, relative to climatic effects, dam impacts are much more direct and often cause abrupt changes in regional hydrologic regimes, thus significantly affecting long-term trends, especially at seasonal and regional scales. Recent analyses of hydrologic changes in large Siberian Rivers demonstrate that, due to reservoir regulation, discharge records collected at the basin outlet do not always represent natural changes and variations; these records tend to underestimate the natural runoff trends in summer and overestimate trends for winter and autumn.
There is a need to document and understand to what extent large dams affect arctic hydrology changes. The PI's research will specifically seek to quantify how large reservoirs impact Siberian regional hydrologic changes. In addition, they will synthesize regional analyses from Canada, Nordic countries and Siberia to achieve a comprehensive pan-Arctic assessment of dam effect on the arctic hydrology system and its past change.
Intellectual merit: Because reservoir regulation is very strong and direct in the northern regions, we must understand dam effects before we can determine hydrologic response to climate change and variation in the large arctic watersheds. Our current knowledge of reservoir effects on arctic hydrologic changes is incomplete and this limits our capability to understand the long-term changes observed in Arctic hydrologic system. This proposed research will clearly document dams and reservoirs in the northern regions and quantitatively assess their impacts on regional hydrologic changes. This knowledge is important to the ARCSS goal of a system-level understanding of the Arctic and its change. This research will produce naturalized streamflow data across Siberia; such data will be valuable for climate model validation and large-scale water budget analyses. These results will advance our understanding of the functions, interactions, and changes in the Arctic system and benefit national and international programs, such as the NSF/ARCSS, HARC, WCRP/GEWEX, and CLIC.
