Water JAM 2010 City of Raleigh briefing for Jordan Lake Partnership October 24, 2014

Water JAM 2010 NC AWWA WEA El El Flood Storage Sed. S. Water Quality Pool Water Supply Pool 20 BG14.7 BG 8.2 BG Falls Lake Storage Profile

Water JAM 2010 NC AWWA WEA 2011 Falls Lake Clayton Gage Illustration of Water Supply Usage Impact on Clayton Flow Target Water Supply Pool Water Quality Pool Raleigh Service Area Flow Target 184 cfs Nov – Mar 254 cfs Apr – Oct NR WWTP 11

Water JAM 2010 NC AWWA WEA Reallocate 4.1 BG of WQ Pool (20.5% of existing WQ Pool) to WS Pool El El Flood Storage Sed. S. Water Quality Pool Water Supply Pool Reallocation Alternative

Water JAM 2010 NC AWWA WEA 2011 Raleigh Quarry Storage with Neuse River Intake below Richland Creek as a Backup 5 EMJ WTP Raleigh Quarry Falls Lake 16

Water JAM 2010 NC AWWA WEA Raleigh Quarry Storage (with Neuse River Intake below Richland Creek as a Backup) Estimated current volume

Water JAM 2010 NC AWWA WEA 2011 River Intake Above Neuse River WWTP 7 Falls Lake Lake Benson Raleigh Service Area Lake Wheeler NR WWTP DE Benton WTP EMJ WTP

Water JAM 2010 NC AWWA WEA River Intake Above Neuse River WWTP Area shaded in green shows potential extent of water supply watershed overlay

Water JAM 2010 NC AWWA WEA 2011 Falls Lake EFDC Model  Developed by NCDENR DWR to aid in developing nutrient management strategy  Completed in 2009 under guidance of Falls Lake Technical Advisory Committee  Simulating Chl-a concentrations was key purpose  Chl-a goal:  Less than 40 µg/L 90% of the time  Focused primarily on nutrient inputs from tributaries  Developed by NCDENR DWR to aid in developing nutrient management strategy  Completed in 2009 under guidance of Falls Lake Technical Advisory Committee  Simulating Chl-a concentrations was key purpose  Chl-a goal:  Less than 40 µg/L 90% of the time  Focused primarily on nutrient inputs from tributaries

Water JAM 2010 NC AWWA WEA 2011 Simulation Scenarios Hydrology Historical Outflow Max WS – Current Allocation Max WS – A.4 Allocation Inflow Chl-a Concentration Unmodified Base Model Inflow Chl-a = 10 µg/L Nutrient Reductions No Nutrient Reductions 40% N 77% P Reductions 12 Total Simulation Scenarios

Water JAM 2010 NC AWWA WEA 2011 Chl-a Exceedance Frequency

Water JAM 2010 NC AWWA WEA 2011 Unmodified Chl-a, Nutrient Reductions

Water JAM 2010 NC AWWA WEA 2011 The dotted grey line above represents simulated historical conditions without nutrient reductions in place, with the grey stars illustrating the observed Chl-a concentrations used for model calibration. Historical withdrawal, current allocation, and A4 allocation lines reflect implementation of 40%N / 77%P reductions.

Water JAM 2010 The grey band illustrates the root mean squared error from model calibration efforts. Measured Chl-a concentrations were generally within µg/L of the concentration simulated for that point in time.

Water JAM 2010 NC AWWA WEA 2011 Other Options?  Reclaimed Water as a Source Water  Jordan Lake Allocation  Reclaimed Water as a Source Water  Jordan Lake Allocation