WORK IN PROGRESS Perspectives on Selecting Water Quality Targets and - PowerPoint PPT Presentation

WORK IN PROGRESS Perspectives on Selecting Water Quality Targets and Allocations September 27, 2012 HDR Engineering, Inc. David Clark, PE Michael Kasch, PE, PH DRAFT Disclaimer: Any opinions, findings, statements, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily ref lect the views of Lower Boise Watershed stakeholders.

 Overview of 303(d) Listing  Monitoring Data  River Conditions Assessment  TMDL Targeting  Cause and Effect Variables  Models and Modeling  Total Phosphorus Spreadsheet Model  Management Scenarios  Linking Targeting with Management  Next Steps DRAFT

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 IDAPA 58.01.02 Water Quality Standards DRAFT

 IDAPA 58.01.02 Water Quality Standards DRAFT

 303(d) listed as impaired needing TMDL DRAFT

 EPA concluded that the Lower Boise River is water quality- limited for nutrients (October 13, 2009)  Basis:  Data on indicators for interpreting narrative criteria  Primary: phosphorus, nitrogen, periphyton chlorophyll a  Additional: turbidity, dissolved oxygen, pH, macrophytes  Comparison Criteria:  Ecoregion criteria of 43 m g/L total phosphorus  Gold Book criteria of 100 m g/L total phosphorus  Reference literature (Welch, Dodds, VNRP, et.al)  10 to 90 m g/L total phosphorus  3 to 60 m g/L soluble reactive phosphorus (SRP)  100 to 200 mg/m 2 chlorophyll a  DEQ’s listing/delisting rationale for other waterbodies  However, metrics were applied on a site-specific basis DRAFT

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 Four locations  # USGS 13203510 BOISE R BL DIVERSION DAM NR BOISE ID  # USGS 13206000 BOISE RIVER AT GLENWOOD BRIDGE NR BOISE ID  # USGS 13210050 BOISE RIVER NR MIDDLETON ID  # USGS 13213000 BOISE RIVER NR PARMA ID  Period of Record Data  Total Nitrogen, Total Phosphorus, N:P Ratio  Suspended Sediment, Orthophosphate, Chlorophyll a DRAFT

8 4 60 Minimum Minimum Minimum 25th 7 3.5 25th 25th 50 Median Total Phosphorus (mg/L) Median Median 6 3 Mean Total Nitrogen (mg/L) Mean Mean 40 75th 5 2.5 Maximum 75th 75th N:P Ratio Limitation Maximum Maximum 4 2 30 3 1.5 20 2 1 10 1 0.5 0 0 0 0 20 40 60 80 0 20 40 60 80 0 20 40 60 80 River Mile River Mile River Mile 250 4 700 Minimum Minimum Minimum Max 664 3.5 600 25th 25th 25th Suspended Sediment (mg/L) 200 Median Median Median Orthophosphate (mg/L) 3 Chlorophyll a (mg/m2) 500 Mean Mean Mean 2.5 150 75th 75th 75th 400 Maximum Maximum Maximum 2 300 100 1.5 200 1 50 100 0.5 DRAFT 0 0 0 0 20 40 60 80 0 20 40 60 80 0 20 40 60 80 River Mile River Mile River Mile

8 4 60 Minimum Minimum Minimum 25th 7 3.5 25th 25th 50 Median Total Phosphorus (mg/L) Median Median 6 3 Mean Total Nitrogen (mg/L) Mean Mean 40 75th 5 2.5 Maximum 75th 75th N:P Ratio Limitation Maximum Maximum 4 2 30 3 1.5 20 2 1 10 1 0.5 0 0 0 0 20 40 60 80 0 20 40 60 80 0 20 40 60 80 River Mile River Mile River Mile 250 4 700 Max 483 Minimum Minimum Minimum 3.5 600 25th 25th 25th Suspended Sediment (mg/L) 200 Median Median Median Orthophosphate (mg/L) 3 Chlorophyll a (mg/m2) 500 Mean Mean Mean 2.5 150 75th 75th 75th 400 Maximum Maximum Maximum 2 300 100 1.5 200 1 50 100 0.5 DRAFT 0 0 0 0 20 40 60 80 0 20 40 60 80 0 20 40 60 80 River Mile River Mile River Mile

8 4 60 Minimum Minimum Minimum 25th 7 3.5 25th 25th 50 Median Total Phosphorus (mg/L) Median Median 6 3 Mean Total Nitrogen (mg/L) Mean Mean 40 75th 5 2.5 Maximum 75th 75th N:P Ratio Limitation Maximum Maximum 4 2 30 3 1.5 20 2 1 10 1 0.5 0 0 0 0 20 40 60 80 0 20 40 60 80 0 20 40 60 80 River Mile River Mile River Mile 250 4 700 Minimum Minimum Minimum Max 664 3.5 600 25th 25th 25th Suspended Sediment (mg/L) 200 Median Median Median Orthophosphate (mg/L) 3 Chlorophyll a (mg/m2) 500 Mean Mean Mean 2.5 150 75th 75th 75th 400 Maximum Maximum Maximum 2 300 100 1.5 200 1 50 100 0.5 DRAFT 0 0 0 0 20 40 60 80 0 20 40 60 80 0 20 40 60 80 River Mile River Mile River Mile

6 1  Median of 2011 Study Minimum Minimum 0.9 25th 25th 5 Median Median 0.8 data are similar Total Phosphorus (mg/L) Mean Mean Total Nitrogen (mg/L) 0.7 75th 75th 4 Maximum Maximum 0.6 to the long-term AS Median, WY09 AS Median, WY09 AS Median, WY10 3 0.5 AS Median, WY10 AS USGS Max AS USGS Max dataset at Parma 0.4 AS USGS Min AS USGS Min 2 0.3 0.2 1 0.1 0 0 0 20 40 60 80 0 20 40 60 80 River Mile River Mile 100 1 Minimum Minimum 90 0.9 25th 25th Median Median Suspended Sediment (mg/L) 80 0.8 Orthophosphate (mg/L) Mean Mean 70 0.7 75th 75th Maximum Maximum 60 0.6 Median, WY09 Median, WY09 50 0.5 Median, WY10 Median, WY10 USGS Max USGS Max 40 0.4 USGS Min USGS Min 30 0.3 20 0.2 10 0.1 DRAFT 0 0 0 20 40 60 80 0 20 40 60 80 River Mile River Mile

Notus  Map – Glenwood Glenwood Parma Hexon and Roswell Rds Middleton Lansing Lane Caldwell Star Chicago St

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 EPA interpreted the narrative standards for  Floating, Suspended or Submerged Matter  Excess nutrients  EPA stated phosphorus levels exceed ecoregional and Gold Book criteria and therefore constitute a violation of the excess nutrient narrative criterion  EPA used 100 to 200 mg/m 2 periphyton chlorophyll a and 43 to 100 m g/L for total phosphorus  Narrative standard “…free from excess nutrients that can cause visible slime growth or other nuisance growths…”  EPA stated that periphyton appears to be the best measure of whether excess nutrients are impairing beneficial uses DRAFT

 Impairment is nuisance algae (EPA)  Visual inspection and complaints indicate nuisance algae  Comparisons of in-stream data and reference criteria indicate nuisance algae  Cause(s) of nuisance algae  Inferred cause is total phosphorus  Evidence: Comparison of in-stream data and reference criteria suggests nuisance algae  Argument  Reduce total phosphorus = reduced nuisance algae  Connection  Not established in EPA letter  Need a site specific analysis to determine the levels of phosphorus in the particular water body that cause nuisance aquatic growths at levels impairing designated beneficial uses. DRAFT

Boise River TMDL Target? • Where? • Middleton to Parma • What? • EPA’s reference criteria • Other • When? • Annual • Seasonal • Other Snake River - Hells Canyon TMDL TP 70 m g/L at Parma DRAFT

 Phosphorus loading spreadsheet does not provide a prediction of Boise River chlorophyll a response  Potential cause [phosphorus] not linked to response [nuisance algae]  “…relations between chlorophyll - a and other water-quality parameters at Parma have not been well characterized…” (USGS, 2011) Core Model August 2000 0.4 8 Total Phosphorus Boise WWTP Lander 0.35 7 Boise WWTP West Boise Boise River chlorophyll a mg/m 2 ??? Source Total Phosphorus (mg/L) Thurman Drain Total Phosphorus (mg/L) 0.3 6 Fifteen Mile Mouth (includes Meridian WWTP) Star Feeder 0.25 5 Long Feeder Watts Creek Mill Slough (includes Star WWTP) 0.2 4 Middleton WWTP Willow Creek @ Middleton 0.15 3 Mason Creek Mason Drain 0.1 2 Hartley (Combined) Caldwell WWTP 0.05 1 Indian Creek (includes Nampa WWTP) DRAFT Conway Gulch @ Notus 0 0 Dixie Drain Near Wilder 0 10 20 30 40 50 60 70 Groundwater River Mile

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 Spreadsheet of Boise River inputs and diversions  Representing conditions from:  August 2000 (medium to low flow year)  July 2001 (low flow year)  Considerations  Use the Core Models to increase understanding of the system  Use the Core Models to investigate potential implications of EPA’s criteria DRAFT

Core Model August 2000 Core Model July 2001 0.4 4,500 0.4 4,500 Total Phosphorus Total Phosphorus 4,000 4,000 0.35 0.35 Flow Flow 3,500 3,500 0.3 0.3 3,000 3,000 Total Phosphorus (mg/L) Total Phosphorus (mg/L) 0.25 0.25 2,500 2,500 Flow (cfs) Flow (cfs) 0.2 0.2 2,000 2,000 0.15 0.15 1,500 1,500 0.1 0.1 1,000 1,000 0.05 0.05 500 500 0 0 0 0 0 10 20 30 40 50 60 70 0 10 20 30 40 50 60 70 River Mile River Mile Downstream Upstream Downstream Upstream DRAFT