1. Southern Willamette Valley 2011 Long-Term Groundwater Monitoring Results

2.  Process of Selection  Balance with other data

5.  Originally established a network of 17 domestic and 26 monitoring wells

6.  DW = Domestic Wells, generally deeper, used on a regular basis  GW = Groundwater Monitoring Wells, generally shallower, purged only when sampled

7. What is being measured  pH  Specific Conductance  Temperature  Dissolved Oxygen  Nitrate  Sulfate (every other time)

8. Sampling Program occurs every 3 months (quarterly) DW Wells take about 2 days GW Wells take about 4-5 days 21 Quarterly events completed, next one is due in Nov. 2011

9.  Changes to Program 2 DW wells were discontinued as they really did not reflect the shallow groundwater used by most GWMA residents (DW-4 & DW-14) One GW Well was dug out as part of a gravel operation (GW-14) Two GW Wells still hit and miss (GW-2 & GW-4S)

10.  Other Changes to Program After the USGS presentation, we decided that for selected wells, we would test for addition parameters along with the current limited suite of analyses  More changes to come

11. Monitoring well __ Land Surface _______________________________________ --------- --------- --------- Depth to Water = 5 feet Depth to Water 15 feet Depth to bottom – usually 23 feet

12.  Over the years, there seems to be some water results from select wells that indicate we are seeing more surface-water influence than groundwater influence.  Wells DW-2, DW-7, GW-16, GW17 and sometimes GW-5 are good examples

15.  All high nitrate-N values in Feb or May  All nitrate-N values <1.5 mg/L in Aug or Nov  Lowest Spec. Cond. in Aug and Nov  Depth to water greatest in Aug and Nov If this was mostly river water influenced – one might think the nitrate would be lowest when the river is the highest (Feb) and the DTW was the lowest (Feb and May)

17. Specific Conductance averaged 237 µmhos/cm Sulfate averaged 11.2 mg/L

21. WellNitrate-N Increase 2011 vs Increase 2010 Nitrate-N Decrease 2011 vs Decrease 2010 Nitrate-N Steady 2011/ Steady 2010 DW4 (2011) 1-2 (2010) 2 (2011) 7 (2010) 8 (2011) 5-6(2010) GW11 (2011) 7 (2010) 4 (2011) 7 (2010) 8 (2011) 9 (2010)

25. What is a 0.71mg/L increase of N to the shallow groundwater equivalent to? Value Unit Average N increase in monitoring wells 0.71 mg/L Area of GWMA 220 mi 2 90% of area 198 mi 2 = 5.5E+09 square feet =126720 acre Average water column in wells Nov 2010-August 2011 12.8 ft

26. What is a 0.71mg/L increase of N to the shallow groundwater equivalent to? Value Unit Average N increase in monitoring wells 0.71 mg/L Area of GWMA 220 mi 2 90% of area 198 mi 2 = 5.5E+09 square feet =126720 acre Average water column in wells Nov 2010-August 2011 12.8 ft Average aquifer 'size' monitored by these wells Nov 2010 - Aug 2010 (yes - not the entire aquifer) 70,655,016,960 ft 3 Cubic feet to liter conversion 2.00073E+12 liters Multiply by average porosity of aquifer (30%) to get the volume of water in aquifer monitored by these wells 600,218,185,407 liters average volume of aquifer

27. Monitoring well __ Land Surface _______________________________________ --------- --------- --------- Depth to Water = 5 feet Depth to Water 15 feet Depth to bottom – usually 23 feet

28. What is a 0.71mg/L increase of N to the shallow groundwater equivalent to? Value Unit Average N increase in monitoring wells 0.71 mg/L Area of GWMA 220 mi 2 90% of area 198 mi 2 = 5.5E+09 square feet =126720 acre Average water column in wells Nov 2010-August 2011 12.8 ft Average aquifer 'size' monitored by these wells Nov 2010 - Aug 2010 (yes - not the entire aquifer) 70,655,016,960 ft 3 Cubic feet to liter conversion 2.00073E+12 liters Multiply by average porosity of aquifer (30%) to get the volume of water in aquifer monitored by these wells 600,218,185,407 liters average volume of aquifer Mult by average GW increase in N = 0.71 mg/L 426,154,911,639 mg of N Convert mg to lbs 939,510 lbs of N Divide by 0.21 (Average N % of Ammonium Sulfate) 4,473,857 lbs of fertilizer equivalent increase in groundwater

29. What is a 0.71mg/L increase of N to the shallow groundwater equivalent to? Value Unit Average N increase in monitoring wells 0.71 mg/L Area of GWMA 220 mi 2 90% of area 198 mi 2 = 5.5E+09 square feet =126720 acre Average water column in wells Nov 2010-August 2011 12.8 ft Average aquifer 'size' monitored by these wells Nov 2010 - Aug 2010 (yes - not the entire aquifer) 70,655,016,960 ft 3 Cubic feet to liter conversion 2.00073E+12 liters Multiply by average porosity of aquifer (30%) to get the volume of water in aquifer monitored by these wells 600,218,185,407 liters average volume of aquifer Mult by average GW increase in N = 0.71 mg/L 426,154,911,639 mg of N Convert mg to lbs 939,510 lbs of N Divide by 0.21 (Average N % of Ammonium Sulfate) 4,473,857 lbs of fertilizer equivalent increase in groundwater Average lbs of fertilizer lost per acre 35 lbs per acre equivalent