2011 Storm impacts on nutrients and sediment in the Susquehanna River Basin Presentation for the Impacts of Tropical Storms Irene and Lee on the Hudson River Hudson River Environmental Society Cary Institute of Ecosystems Studies Wednesday September 19, 2012 Kevin McGonigal Environmental Scientist Susquehanna River Basin Commission

Site Location Drainage Area (Sq. Mi.) Water/ Wetland UrbanAgForest Towanda7, Marietta25, Where Towanda – Mostly NY Marietta – Above Dams What Precipitation Flows Loads Average Concentrations When September 6-day peak flow period How Estimator

Precip Inches September 2004September 2011 PrecipDeparturePrecipDeparture NY PA Source data at: September Flow Daily High 2011 Monthly Average Monthly % of LTM Towanda ,00027,943491% ,00036,785647% LTM 5,687 March ,00047,732202% Marietta ,000*110,893465% ,000137,867578% LTM 23,610 March ,000162,713217%

September Loads in Tons TowandaDaily HighAve Mon QTNTPSS ,00027,9431, ,588, ,00036,7852, ,020,671 LTM5, ,844 March ,00047,7324, ,135 MariettaAve Mon QTNTPSS ,000*110,89314,2033,4597,333, ,000137,86715,2424,71212,014,186 LTM23,6102, ,628 March ,000162,71318,8541,6502,342,749

September Average Concentrations mg/L TowandaAve Mon QTNTPSS , , ,688 LTM5, MariettaAve Mon QTNTPSS , , ,078 LTM23,

Focus on Suspended Sediment SS Tons 2011 TowandaMarietta 2011LTM2011LTM March578,135214,9442,342,739517,595 April818,977348,3032,363,189586,536 September5,020,67181,07912,014,186364,647 3 Mo Total6,417,783644,32616,720,1141,468,777 Annual6,848,6591,660,53219,071,8383,888,205

day totals Towanda Ave FlowDaily HighSS Tons March ,850124,000182,501 April ,033128,000294,713 Sept ,717250,0003,158, day totals Marietta Ave FlowHigh Daily AveSS Tons March ,833434,000816,043 April ,667370,000720,619 Sept ,167664,0006,800,111 6-Day loads over peak of storm events

September Towanda YearDaysAve FlowHigh daily Ave.SS TonsAc-ft Ivan ,216127,000809, Lee ,717220,0003,158,7672,447

Time Periods (Months)% FlowTNTP% SS Top 10% flow10.09%10.06%18.17%28.73% (top 3 SS)3.95%4.03%11.83%23.75% (September)2.03%1.81%8.17%19.90% 2011 (March, April, September)3.70%3.03%7.92%17.20% 2011 (September)1.12%0.94%4.71%12.36% Historical High SS Comparison At Marietta 25 years

Take home The “bad” Individual high flow events versus sustained high flows Increases in sediment due to scour of reservoirs The “good” Timing of storms At end of summer

??Questions/Comments?? Image taken August 30 8/30/11 max 83,500 cfs Image taken September 13 9/9/11 max 778,000 cfs (>390,000 cfs = scour - USGS) Satellite Image Source Columbia, PA South of Route 462 aka Marietta Site 9/10/11