Focus Group Meeting: November 12, 2013 Truckee River Water Quality Standards Review

Overview of Topics for Discussion Welcome and introductions Feedback from previous workshop Technical Updates – Updated (DRAFT final) model simulation results – Climate sensitivity runs – Mapping of restoration sites in context of model domain Next steps – Technical report development and review – NDEP timeline – Focus Group involvement in

Feedback from Previous Workshop?

Updated (Draft Final) Model Simulation Results

Summary of Final Adjustments Final Model Adjustments – wrapping up loose ends – Minor low flow year adjustments -- closer to 10 th percentile targets – Resolved DO concentration initial condition issue – Extended simulations across full range of WQ concentrations – Shifted curves to actual instream (not target) nutrient concentrations Results: – No major surprises

Representative Flow Conditions Derived “target flows” based on TROM Future No Action output Two representative flow regimes – Low Flow (10 th percentile) – Average Flow (50 th percentile) 6

Low Flow Regime: TROM 1977 FNA, 10 th percentile targets, TRHSPF 7 Adjusted at WARMF-TRHSPF interface – July, August decreased flow – September increased flow Adjusted summer period for lower river Adjusted at Sparks Jul - Sep Adjusted at TCID

Average Flow Regime: TROM 1985 FNA, 10 th percentile targets, TRHSPF 8 No additional adjustment

Set of Simulations Orthophosphate (mg/L) Total Nitrogen (mg/L) PLPT std x 0.65 x 0.75 NDEP/PLPT std xxxxx 0.85 x 1.00 x Total Phosphorus (mg/L) Total Nitrogen (mg/L) NDEP std x 0.65 x 0.75 NDEP/PLPT std xx xxxx 0.85 x 1.00 x

Spatial Aggregation for WQS Modeling 10

Options for Calculating Percent Violation of DO WQS 11 % of Hours: attainment is aggregation of all hours that have violated WQS X hours violated 8760 hours/yr % of Days: if 1 + hours violate WQS on a given day, that day is not in attainment X days violated 365 days/yr Reviewing attainment as “% of days” is more conservative approach

Normalized Nutrient Concentrations in DO Compliance Curves Target concentrations set at upper model boundaries Adjusted loads at major sources of load input (Steamboat Cr., N. Truckee Drain, lower river agricultural input) Slight variation in concentrations longitudinally Plotted “actual” instead of “target” concentration on x-axis For TN plots, also shifted Y-axis for Ortho-P curve 12

Example of Curve Normalization 13 Horizontal Shift for OP evaluation Vertical Shift of OP line for TN evaluation (Reach 4 only)

DRAFT Final Results Total P 10 th Percentile Flow: Reach Averaged 14 % of Days% of Hours TN = 0.75

DRAFT Final Results Ortho-P 10 th Percentile Flow: Reach Averaged 15 % of Days% of Hours TN = 0.75

DRAFT Final Results Total Nitrogen 10 th Percentile Flow: Reach Averaged 16 % of Days% of Hours

Longitudinal Plot: Low Flow Year (DRAFT Final) 17 TN = 0.75 mg/L OP = 0.05 mg/L TN = 0.75 mg/L TP = 0.05 mg/L

DRAFT Final Results Total P 50 th Percentile Flow: Reach Averaged 18 % of Days% of Hours TN = 0.75

DRAFT Final Results Ortho P 50 th Percentile Flow: Reach Averaged 19 % of Days% of Hours TN = 0.75

DRAFT Final Results Total N 50 th Percentile Flow: Reach Averaged 20 % of Days% of Hours

Longitudinal Plot: Average Flow Year (DRAFT Final) 21 TN = 0.75 mg/L OP = 0.05 mg/L TN = 0.75 mg/L TP = 0.05 mg/L

Summary of DO Compliance (DRAFT Final) Crosshairs run: TN 0.75 / TP 0.05 and TN 0.75 / OP Location TP = 0.05 (OP ~ 0.028)OP = 0.05 (TP ~ 0.094) % of Days in Violation % of Hours in Violation % of Days in Violation % of Hours in Violation Low FlowAve FlowLow FlowAve FlowLow FlowAve FlowLow FlowAve Flow Aggregated Reach Reach Reach Reach Most Critical Reaches Vista Tracy Below Derby Marble Bluff Dam

Summary of DO Compliance (DRAFT Final) Crosshairs run: TN 0.75 / TP 0.05 and TN 0.75 / OP Location TP = 0.05 (OP ~ 0.028)OP = 0.05 (TP ~ 0.094) % of Days in Violation % of Hours in Violation % of Days in Violation % of Hours in Violation Low FlowAve FlowLow FlowAve FlowLow FlowAve FlowLow FlowAve Flow Aggregated Reach Reach Reach Reach Most Critical Reaches Vista Tracy Below Derby Marble Bluff Dam Shading denotes existing phosphorus WQS

Observations Reaches 1, 2, 3 show low level of DO violation Reach 4 is most critical at 10 th percentile flow – Sensitive to the phosphorus concentration – Not sensitive to the TN concentration – No violations for 50 th percentile flows DO violations in Reach 4 sensitive to other factors beyond P concentration – Flow condition – Channel geometry 24

Integration of Results Over Full Flow Regime Results to date have focused on low and average flow conditions Also evaluated integrated DO violations (DOv) across all flow regimes: DOv all = 0.2*DOv low + 0.6* DOv ave + 0.2*DOv high Spreadsheet calculation 90 th percentile year not simulated – Conservative assumption: DOv high = DOv ave 25

Integration Over Flow Regimes: Compare Target Flows 26

Integrated Flow: Reached Averaged 27 % violations in Reach 4 (PLPT) much lower when integrating over all flows than for only the low flow year TPOrtho-P

Interpretation of WQS Modeling Results LimnoTech will summarize technical results in a report NDEP/EPA will determine recommendations for any potential change from existing WQS 28

Climate Sensitivity Runs

General Approach for Climate Sensitivity Runs Simulated “cross hairs” run for each flow regime – TN 0.75 mg/L, Ortho-P 0.05 mg/L – TN 0.75 mg/L, TP 0.05 mg/L Adjusted TRHSPF temperature inputs: air water exchange – Applied a 1° C air temperature increase across entire year – First iteration run to estimate maximum water temperature increase (near Marble Bluff Dam) – Applied ΔT ° C water temperature increase at WARMF / TRHSPF interface (McCarran, North Truckee Drain, Steamboat Creek) 30

Climate Sensitivity Simulation: 10 th Percentile Flow 31 % of Days % of Hours Modest increase in percent DO violations with increased air and water temperature

Climate Sensitivity Simulation: 50 th Percentile Flow 32 % of Days % of Hours Modest increase in percent DO violations with increased air and water temperature

Mapping of Restoration Sites

River Geomorphology and Restoration Model is a conservative representation of actual river – TRHSPF parameterized for pre-restoration geometry condition Mapped completed, ongoing and planned restoration activity Supplementary information to include in technical report

35 Vista (304) Tracy (315) Marble Bluff Dam (343) Below Derby Dam (320)

Next Steps 36

LimnoTech Technical Report Introduction – Watershed, justification for effort, WQS review process, stakeholder outreach Summary of models (development, calibration) Overview of WQS model application approach Development of representative flow condition Simulation of DO response to nutrient concentrations – Low Flow Condition – Average Flow Condition – Integration Over full Flow Regime Discussion of results Additional considerations – River geometry properties – River restoration – Climate change sensitivity Observations and conclusions for revision of WQS Appendices: – Focus Group outreach, comments – Detailed technical information 37

NDEP Timeline 12/1/2013: Preliminary Draft LimnoTech report on modeling 1/1/2014: Review completed by Working Group 1/15/2014: Draft LimnoTech report on modeling results Mid Jan: NDEP Public workshop 2/15/2014: Review completed by Focus Group 3/1/2014: Final LimnoTech report on modeling results 4/1/2014: Draft NDEP Rationale/Petition for proposed standards changes 5/1/2014: NDEP Workshops – Focus Group, general public 6/30/2014: Final NDEP Rationale/Petition to LCB 38

Focus Group Involvement 2014 Focus Group Meeting: Jan 15, 2014 – Overview of Technical Report document Review of Technical Report – Comments due 2/15/2014 Additional Stakeholder / Focus Group meetings TBD in

Extras 40

“Crosshairs” Simulation for Testing Orthophosphate (mg/L) Total Nitrogen (mg/L) PLPT std x 0.65 x 0.75 NDEP/PLPT std xxxxx 0.85 x 1.00 x Total Phosphorus (mg/L) Total Nitrogen (mg/L) NDEP std x 0.65 x 0.75 NDEP/PLPT std xx xxxx 0.85 x 1.00 x

River Geomorphology and Restoration Supplementary information to include with analysis Potential relationship between channel geometry and most critical segments Developed and mapped “indicator” of potentially vulnerable regions – Based on depth, velocity, slope Mapped restoration activity Model is a conservative representation of actual river – TRHSPF parameterized for pre-restoration geometry condition

Reach Geometry Index 43 Vista (304) Tracy (315) Marble Bluff Dam (343) Below Derby Dam (320)