Long-term Monitoring of the Des Moines River Donna S. Lutz Des Moines River Water Quality Network Presented at the Des Moines Water Works January 28, 2008

What is the Des Moines River Water Quality Network? Initiated in July 1967 as preimpoundment study for Saylorville Reservoir, expanded to Red Rock Reservoir in 1971 Long-term record, 40 years at many sites, total of 252 parameters, about 485,000 individual data records Currently 7 regular sampling sites, monitored 22 times per year for up to 50 parameters Data available through annual reports, paradox database, & project webpage

Des Moines River Basin Length 535 mi Width 50 mi Basin 12,884 sq mi about ¼ size of Iowa Saylorville Reservoir 24 mi valley/54 mi flood 5,520 acres/ 16,100 flood 1,100 ac-ft/yr sedimentation Red Rock Reservoir 18 mi valley/33 mi flood 15,250 acres/ 1,625,00 fl 4,470 ac-ft/yr sedimentation

Raccoon River Sub-basin North Raccoon/Middle Raccoon/South Raccoon Basin 3,411 sq mi

Routine Parameters Physical Physical temperature, flow/elevation temperature, flow/elevation turbidity, secchi disc depth, gas saturation turbidity, secchi disc depth, gas saturation Chemical Chemical dissolved oxygen, BOD, TOC, nutrients, suspended solids dissolved oxygen, BOD, TOC, nutrients, suspended solids metals, pesticides metals, pesticides Biological Biological chlorophyll pigments chlorophyll pigments bacteria bacteria

Important Programs: Short-term Bacteria Bacteria River, reservoir and beaches River, reservoir and beaches Is it safe to swim, wade? Is it safe to swim, wade? State of Iowa WQ Stds State of Iowa WQ Stds Based on E Coli Based on E Coli Class A1 & A3 (1 o & children) Class A1 & A3 (1 o & children) geomean 126 /100ml geomean 126 /100ml Sample max 235 /100ml Sample max 235 /100ml Class A2 (2 o contact) Class A2 (2 o contact) geomean 630/100ml geomean 630/100ml Sample max 2,880 /100ml Sample max 2,880 /100ml Bacteria Monitoring

Important Programs: Short-term Are they safe to eat? Are they safe to eat? For people and critters For people and critters Cyprinus carpio Cyprinus carpio Fillets (28 yr) Whole (20 yr) Fillets (28 yr) Whole (20 yr) Dieldrin, Chlordane, Heptachlor epoxide, Alachlor, Trifluralin and Chlorpyrifos Dieldrin, Chlordane, Heptachlor epoxide, Alachlor, Trifluralin and Chlorpyrifos Electrofishing on Iowa River Pesticides in Fish

Important Programs: Short-term Fish Kill Investigations Fish Kill Investigations Thermal Stress Thermal Stress Dorosoma cepedianum Dorosoma cepedianum Large kills, one species, similar size Large kills, one species, similar size Gas Supersaturation Gas Supersaturation Minor to large kills, many species and size ranges Minor to large kills, many species and size ranges Either extreme gas pressure or lowered outflow Either extreme gas pressure or lowered outflow

Important Programs: Short-term What’s Up? What’s Up? Why is water so foamy? Why is water so foamy? Oily? Oily? Green? Green?

Important Programs: Long-term What is normal? What is normal? Is water quality improving? (degrading or can’t tell?) Is water quality improving? (degrading or can’t tell?) Major Players Major Players Nutrients Nutrients Pesticides Pesticides Chlorophyll Chlorophyll Bacteria Bacteria WQI WQI

Significant Findings Non-point sources are the main contaminants ; Non-point sources are the main contaminants ; soil erosion and siltation primary resource problem soil erosion and siltation primary resource problem Ave. loading to Red Rock 5,400 metric tons/day Ave. loading to Red Rock 5,400 metric tons/day Point source loading has decreased Point source loading has decreased Improved wastewater treatment has significantly reduced ammonia loading Improved wastewater treatment has significantly reduced ammonia loading Nitrate levels have increased, with the greatest increases seen , paralleling increases in N fertilizer use Nitrate levels have increased, with the greatest increases seen , paralleling increases in N fertilizer use Total Phosphate levels have decreased slightly, but only by about 0.01 mg/year Total Phosphate levels have decreased slightly, but only by about 0.01 mg/year

Significant Findings (cont’d) Overall, water quality has significantly improved at most sites, according to water quality index values Overall, water quality has significantly improved at most sites, according to water quality index values Pesticide levels in fish are low, but may still be of concern Pesticide levels in fish are low, but may still be of concern Gas supersaturation-induced gas bubble trauma causes periodic fish kills below Red Rock Dam Gas supersaturation-induced gas bubble trauma causes periodic fish kills below Red Rock Dam

DMRWQN Website Project description, site photos Project description, site photos Monitoring event data, monthly & annual reports Monitoring event data, monthly & annual reports Beach bacteria data Beach bacteria data Long-term data available from Lutz or website Long-term data available from Lutz or website Acknowledge source, ie RI Corps Acknowledge source, ie RI Corps Provide us with analysis or report Provide us with analysis or report

Monitoring Event Report

Annual Report

Focus on Nitrite +Nitrate N Ammonia oxidized to nitrate (bacterially mediated) Ammonia oxidized to nitrate (bacterially mediated) Nitrite, intermediate product, ( , max 0.68 mg/l, 99% of samples <0.20 mg/l) Nitrite, intermediate product, ( , max 0.68 mg/l, 99% of samples <0.20 mg/l) Sources Sources Fertilizers, oxidation or organic N, fixation of N 2, precipitation, sewage effluents Fertilizers, oxidation or organic N, fixation of N 2, precipitation, sewage effluents Losses Losses Leaching, assimilation living organisms, conversion to other forms Leaching, assimilation living organisms, conversion to other forms Soluble, easily leaches from soil Soluble, easily leaches from soil TRANSFORMS & MOVES with WATER

Results – Streamflow Changes

Regression Models Relating Baseflow to Nitrate Qb provided best r 2 value (0.61) compared to Q (0.59), Qs (0.48) or Q% (0.27)

What is normal? Des Moines River at Boone Des Moines River at Boone 40 yr annual average, 5.86 mg/l 40 yr annual average, 5.86 mg/l Raccoon River at Van Meter Raccoon River at Van Meter 35 yr annual average, 7.07 mg/l 35 yr annual average, 7.07 mg/l → Was 2007 water year unusual? DMR 7.11 mg/l Raccoon R 9.58 mg/l

Are nitrate concentrations increasing? Data is not normally distributed so used non-parametric statistics Data is not normally distributed so used non-parametric statistics Loftis and Ward, Colorado State University - tested 7 statistical tests Recommend Seasonal Kendall test Loftis and Ward, Colorado State University - tested 7 statistical tests Recommend Seasonal Kendall test Data was flow-adjusted – influence of climatic events removed Data was flow-adjusted – influence of climatic events removed Need to use statistical techniques to discern and describe trends

Seasonal Kendall Tau Trend Analysis, Significant Trends (95%) (from Monthly Mean Data, flow-adjusted) NO2+NO3 N

Nitrogen Fertilizer Use and Corn Acres Planted

Raccoon R at Van Meter, Recent data shows increasing trend 0.14 mg/l/yr *but only at 90% confidence

DMR at Boone, Recent data shows increasing trend 0.26 mg/l/yr

What this means to DMWW Nitrate concentrations are increasing in the Raccoon River, currently at a rate of 0.15mg/l/yr Nitrate concentrations are increasing in the Raccoon River, currently at a rate of 0.15mg/l/yr Is the 10 mg/l drinking water standard being exceeded more often? Yes, in the Des Moines River, maybe in the Raccoon River. Is the 10 mg/l drinking water standard being exceeded more often? Yes, in the Des Moines River, maybe in the Raccoon River.

Overall, is water quality better? Yes, according to WQI Yes, according to WQI DMR WQI based on DMR WQI based on %DO (0.21) %DO (0.21) pH (0.14) pH (0.14) BOD (0.14) BOD (0.14) NO 2 +NO 3 NO 2 +NO 3 (0.13) Ammonia (0.17) Turbidity + Sus Solids (0.21)

For more information

If interested contact me about statistical methods employed