Location: Watershed Management ResearchTitle: Prediction of seasonal runoff in ungauged basins Author
|Marks, Daniel - Danny|
Submitted to: International Association of Hydrological Science
Publication Type: Book / Chapter
Publication Acceptance Date: 8/1/2012
Publication Date: N/A
Citation: N/A Interpretive Summary: The seasonal delivery of water from, particularly from mountainous regions is difficult to forecast. This primarily because of limited measurements and uncertain climate conditions. Though significant advances have been made in statistical modeling and calibration, climate instability primarily caused by anthropogenic global warming has limited the utility of these methods. As the climate continues to warm, current water supply forecasting tools will become increasingly ineffective. It is critical that we develop new methods of data collection and physics-based models for predicting the hydrologic response from regions dominated by snow and cold season precipitation and seasonally varying streamflow.
Technical Abstract: Many regions of the world experience strong seasonality in climate (i.e. precipitation and temperature), and strong seasonal runoff variability. Predictable patterns in seasonal water availability are of significant benefit to society because they allow reliable planning and infrastructure development to supply water for agriculture (food production), municipal use (drinking water) and energy (hydropower production); and to efficiently allocate water between competing end users, including ecosystems. In Norway, the reliability of seasonal runoff has enabled that country to depend almost exclusively on hydropower for its energy needs. Human settlements in the vast Gangetic plain in northern India have historically depended on reliable seasonal runoff, including snowmelt, generated in the Himalayas. Figure 6.1 presents the hyetograph of estimated areal average precipitation over the Upper Ganges basin (87,000 km2) and the runoff hydrograph measured near Kanpur (Bharati et al., 2011). There is a regular pattern in the seasonal runoff that mirrors seasonality in precipitation, which is also influenced by a strong orographic effect in this part of the world. While reliability in seasonal runoff (where it exists) confers much benefit to society, unpredictability in the magnitude and timing of precipitation and runoff events can lead to frequent unplanned water shortages and human suffering. In the Indian example, however, the construction of dams and water infrastructure all along the river, a changing monsoon regime, and rising temperatures are all starting to alter the magnitude and timing of runoff in the Upper Ganges, with concerns that these changes and the resulting lack of reliability have the potential to adversely impact millions of people further downstream (Bharati et al., 2011). Indeed, several nations in South Asia already regularly suffer from the lack of predictability and reliability of monsoonal precipitation, so this has become a recurring problem.