Presented to Minnesota Water Resources Conference Oct 14 – 15, 2014 Regional Progress in Water Quality ---- A Trend Analysis for Select Streams in the Twin-Cities Metro Area This study is part of stream assessment report. If you would like to know details about the report, you can stop by our post during the break and our website as well. We have the assessment results for St Croix River tributaries published n our website and other chapters for Missi R and MN r tributaries will be posted soon. Currently, I am also working on the river water quality assessment report, which will be completed in next one or two years. And by the time, I will be able to present to you the second part of the regional progress in QW ---- rivers. H. Wang, K. Jensen, J. Kostrzewski, E. Resseger, T. O’Dea, J. Mulcahy and J. Sventek Metropolitan Council Environmental Services, St Paul, MN Presented to Minnesota Water Resources Conference Oct 14 – 15, 2014

Acknowledgements MCES Water Resources Assessment Group MCES Environmental Monitoring Group David Lorenz – USGS, Mounds View, MN Skip Vecchia – USGS, Bismarck, ND We are working closely with USGS staff to apply the model to the metro streams for water quality trends Presented to Minnesota Water Resources Conference Oct 14 – 15, 2014

Outline QWTREND Statistical Model and Application Case Studies - Vermillion River and Bassett Creek Regional Water Quality Trend and Comparison Conclusions Presented to Minnesota Water Resources Conference Oct 14 – 15, 2014

Water Quality Trend --- External Factors --- Natural Processes Precipitation/runoff Seasonal changes Wet and drought years Climate changes Human Activities Agricultural practices and urban development BMPs for non-point pollution sources Point source discharges and control as you know WQ is affected by many factors. First of course, the natural processes such as precipitation and seasonal variations. Second is human activities. Impacts by those two processes could be complicated . For example, BMPs can reduce pollution loads and improve water quality. however, those efforts can also be offset by increases in surface runoff and flow due to seasonal, annual and long-term climate changes. Presented to Minnesota Water Resources Conference Oct 14 – 15, 2014

Water Quality Trend --- Trend Types --- Non-Flow-Adjusted Trends ---- The overall trends resulting from both natural and human factors Flow-Adjusted Trends ---- The trends that would have occurred in the absence of natural stream flow variability Therefore, we divide WQ trends into two types of trends: non-flow adjusted and flow adjusted. In our trend analysis, we are trying to identify the flow-adjusted trend using QWTREND model to remove impact of flow variability Presented to Minnesota Water Resources Conference Oct 14 – 15, 2014

What is QWTREND? Short for Quality of Water TREND A statistical program developed by USGS A time series model accounting for seasonality and complex flow-related variability Ability to analyze multiple and long-term water quality trends So what is QWTREND. QWTREND is statistical program --- short of quality of water trend developed by USGS. The model has been used by USGS for many projects national wide and recently used by MPCA for statewide nitrogen study Different from traditional methods such as Kendal Tau, which only provide monotonic trend, QWTREND has ability to identify multiple trends for a water body Presented to Minnesota Water Resources Conference Oct 14 – 15, 2014

QWTREND Model Log C(t) = M + SEAS + SRA + TND + PRDEV + NOISE M is the long term mean SEAS is seasonality SRA is the stream flow-related anomaly TND is the long-term trend PRDEV is predicted deviation Noise is the prediction error QWTREND models pollutant concentration in logarithm and separate the concentration variability into different components, including trend Presented to Minnesota Water Resources Conference Oct 14 – 15, 2014

QWTREND Data Requirements At least 15 years of water quality records Average of at least 4 samples per year At least 10 samples within each quarter of the year over a 15-year period Less than 10% of values below detection limit Complete daily flow record for the assessment periods plus precedent five years The model has several minimum data input requirements, in which most important is you have to have at least 15 years QW data, particularly daily flow. Thanks to the great job of our monitoring group, MC has very good monitoring data. Most meet the requirements Presented to Minnesota Water Resources Conference Oct 14 – 15, 2014

QWTREND Assessment Criteria Akaike Information Criteria (AIC) AIC = (-2lnL) + (2*Parameters) p-value p =1-pchisq((-2lnL)initial - (-2ln L)linear, Trends) p-value for this study: 0.05 for one-trend model To identify if trend exists, we use two statistical metrics, which are kind of quality control --- a relative measure of the goodness of fit of a statistical model (AICLinear < AICInitial) -----an index for statistical significance of the modeled trends (0.1 > P > 0.01) Presented to Minnesota Water Resources Conference Oct 14 – 15, 2014

Stream Monitoring Stations in the Metro Area The Metropolitan Council currently collects both water quality and stream flow information at 23 stream sites and some stations started 1989. The program covers about 50% of watersheds in the metro areas and provides excellent data set for water quality assessment and management Presented to Minnesota Water Resources Conference Oct 14 – 15, 2014

Stream Selection and Data Availability Streams and monitoring stations 9 Mississippi River tributaries 9 Minnesota River tributaries 2 St. Croix River tributaries Parameters Total suspended solids Total phosphorus Nitrate Varying water quality records Based on availability of data, we chosen 20 streams for trend assessment Those three traditional parameters are assessed to present the WQ Most streams have more than 15 yr data but few have 12 -1 3 years Presented to Minnesota Water Resources Conference Oct 14 – 15, 2014

Case Study (1) --- Vermillion River One of the largest tributaries Empire WWTP discharged to the river since 1976 -2008 TP impacted by effluent Bio-P removal applied from 2006 Trout stream Presented to Minnesota Water Resources Conference Oct 14 – 15, 2014

Case Study (1) --- Vermillion River TSS One downward trend with 65% decrease Last 5 yr: decreased by 19% at 0.33 mg/l/yr in the Decreasing TSS Presented to Minnesota Water Resources Conference Oct 14 – 15, 2014

Case Study (1) --- Vermillion River TP 1995 - 2005: increased by 76% 2006 : sharply decreased by 89% 2007 – 2008: slow decreased by 28% 2009 – 2012: faster decreased by 45% Last 5 yr: decreased by 53% at 0.01 mg/l/yr Decreasing TP Presented to Minnesota Water Resources Conference Oct 14 – 15, 2014

Case Study (1) --- Vermillion River Nitrate 1998 - 2000: increased by 89% 2001 – 2012: decreased by 49% Last 5 yr: decreased by 21% at 0.19 mg/l/yr Decreasing nitrate Presented to Minnesota Water Resources Conference Oct 14 – 15, 2014

Case Study (2) --- Bassett Creek Urbanized watershed (64%) No major point sources A number of BMPS implemented Storm water ponds Channel restorations Herbicide application a number of water quality improvements have been made within the watershed. Water quality ponds were constructed to treat stormwater runoff Presented to Minnesota Water Resources Conference Oct 14 – 15, 2014

Case Study (2) --- Bassett Creek TP TSS NO3 Cl- a number of water quality improvements have been made within the watershed. Water quality ponds were constructed to treat stormwater runoff Presented to Minnesota Water Resources Conference Oct 14 – 15, 2014

Deterioration Improvement Regional Progress in WQ ---- Mississippi River Tributaries (2008 – 2012) ---- Deterioration Improvement Presented to Minnesota Water Resources Conference Oct 14 – 15, 2014

Deterioration Improvement Regional Progress in WQ ---- Minnesota and St. Croix River Tributaries (2008 – 2012) ---- Deterioration Improvement Sand Creek TSS actually fluctuated during the assessment period from 1990 to 2012. But a unfortunately TSS increase during the last five years probably due to heavy storm and bank failure. No TP and nitrate trends were reported for Eagle Creek, and no TP trend was for Willow Creek Increasing TSS and TP trends in Browns Creek are likely due to the disturbance of sediment and soil during the construction phase of major stream restoration projects. Valley Creek has substantial ground water nitrate contribution. Presented to Minnesota Water Resources Conference Oct 14 – 15, 2014

Regional Map of Modeled Trend ---- TSS Concentration ---- Three colors Blue represent concentrations decreased more than -3% Yellow represent the concentration varied with -3% - 3% Red represent the concentration increased more than 3% Presented to Minnesota Water Resources Conference Oct 14 – 15, 2014

Regional Map of Modeled Trend ---- TP Concentration ---- Presented to Minnesota Water Resources Conference Oct 14 – 15, 2014

Regional Map of Modeled Trend ---- Nitrate Concentration ---- Presented to Minnesota Water Resources Conference Oct 14 – 15, 2014

Potential Factors Linked to Improving WQ The Clean Water Act in 1972 State-wide reduction in wastewater treatment plant (WWTP) phosphorus discharges The Minnesota Phosphorus Lawn Fertilizer Law implemented in 2002 Ag programs The Metropolitan Surface Water Management Act in 1982 Educational programs Grants to fund construction of water quality practices Environmental non-profits The Minnesota State Storm-water Manual in 2005 People may interest in to know what contributes to our great progress in WQ regional wide. To link the trends to the cause, we need work closed with local watershed management organization. But in general, I believe that many pollution control and management programs are contributing this improvement. They include federal level the clean water Act which push impaired water assessment and TMDL study, and also many state, regional and watershed level programs, efforts by non-profit organization and so on. Presented to Minnesota Water Resources Conference Oct 14 – 15, 2014

Conclusions Of the 20 streams assessed, most exhibited a substantial improvement in water quality 17 showed decreasing TSS and TP concentrations 16 had decreasing NO3 concentration None of the streams had decreasing water quality for all three parameters There was no identifiable spatial pattern for the streams with increasing or decreasing water quality Presented to Minnesota Water Resources Conference Oct 14 – 15, 2014

Thank You! Question? Dr. Hong Wang Principal Environmental Scientist Metropolitan Council  Environmental Services hong.wang@metc.state.mn.us P. 651.602.1079  |  F. 651.602.1130 390 North Robert Street, St. Paul, MN55101 metrocouncil.org        Presented to Minnesota Water Resources Conference Oct 14 – 15, 2014