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Research reports and study findings related to hydropower
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Research under way on sediment in the Lower Susquehanna River

Scientists with the University of Maryland Center for Environmental Science have undertaken a two-year study to quantify the amount of sediment and associated nutrients present in major entry points to the Lower Susquehanna River Reservoir System and upper Chesapeake Bay.

This work builds on a recent assessment led by the U.S. Army Corps of Engineers that analyzed the movement of sediment and associated nutrient loads through the watershed to the upper bay. Special emphasis will be given to sediment and nutrient loads into and out of Conowingo Pond, impounded by Conowingo Dam, during high flow events.

Sediment collects behind all dams on the Lower Susquehanna River, and major storms scour out some of this sediment and send it downstream, along with sediment-laden runoff from Pennsylvania and New York. Research will measure how much phosphorous and nitrogen is attached to these sediment particles and determine the effect of these sediments and associated nutrients in the bay.

Among the overarching issues that the research will address is the degree to which sediments and attached nutrients scoured during high-flow events may reduce Maryland’s ability to meet the total maximum daily load goals for 2025 established by the Environmental Protection Agency and the affected states. Research will help determine what additional nutrient load reductions are required to balance the existing “pollution diet” during the Chesapeake Bay program’s mid-point assessment in 2017.

Study reveals impact of tsunami on the Columbia River

A major tsunami event would have little impact on water levels around the Portland area and at Bonneville Dam but water could rise as much as 13 feet just inside the mouth of the Columbia River. These are just two findings from a study recently completed by Oregon State University engineers.

The study was intended to evaluate the impact of a major tsunami event on the river, as well as what forces are most important in controlling water flow and what areas might be inundated.

The researchers found that tidal stages are far more important than river flow in determining the impact of a tsunami. They also determined that a major tsunami event would have its greatest effect at the highest tides of the year and that a tsunami would be largely dissipated within about 50 miles of the river’s mouth.

Many variables can dampen or magnify the effect of tsunamis on rivers, including the width and shape of river mouths, bays, river flow and tidal effects. Because the major tsunami in Japan in 2011 also included significant inland reach and damage on local rivers, researchers are paying increased attention to the risks facing residents along such rivers.

Studying a maximum 9.0 magnitude earthquake and associated tsunamis, researchers concluded that at the highest tide of the year, the tsunami would raise water levels about 11.5 to 13 feet. The effect would decrease at distance upriver, with no measurable rise in the river at river mile 50.

For more, visit http://oregonstate.edu/ua/ncs/archives/2015/feb/study-outlines-impact-tsunami-columbia-river.

Climate change may increase irrigation demand, evaporation

A http://www.usbr.gov/WaterSMART/wcra report issued by the U.S Department of Interior’s Bureau of Reclamation reveals that irrigation water requirements may increase over the second half of the 21st century at the same time as annual evaporation at reservoirs is increasing.

These findings could impact hydropower generation, as Reclamation is the second largest producer of hydroelectric power in the U.S.

The study evaluated irrigation water requirements across eight major river basins for the second half of the 20th century and, as compared to projected demand for the second half of the 21st century, found that net irrigation water requirements in the West may be 6% higher. The study also revealed that, based on a projected temperature increase of about 5 degrees Fahrenheit, annual evaporation at most of the 12 reservoirs modeled could increase 2 to 6 inches by 2080.

The report is the latest in a series of West-Wide Climate Risk Assessments — analyses of overall impacts from climate change on water resources.

Reclamation Commissioner Estevan Lopez said the study provided important information about climate change imposing stresses on water resources and will help inform water planners and stakeholders in confronting future climate-related supply and demand challenges.

Scientists considered projected irrigation demand in eight river basins. The water evaporation model was applied to 12 reservoirs.

The report may be found at www.usbr.gov/WaterSMART/wcra.

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