SCENARIO PLANNING FOR WATER AND WASTEWATER IN THE TRUCKEE MEADOWS NNWPC Agenda Item 9 Jeremy M. Smith, TMRPA Jim Smitherman, WRWC 8/3/2016
Outline Background Future growth outlook and spatial modeling TMWA water use factors and model calculations Water demand Winter water use (proxy for wastewater) Validation with observed data Projection of future water demand and wastewater generation Multiple scenarios Spatially-enabled results
TMRPA Partnership with WRWC GIS support for water and wastewater planning Regional Water Management Plan Regional Plan Scenario planning Consensus forecast Spatial modeling of population and employment forecasts TMRPA housing study Pattern linked to cost of infrastructure
Washoe County Consensus Forecast Assessment of forecasted population and employment growth; performed every 2 years by TMRPA to inform planning efforts across the region. Sources Nevada State Demographer Truckee Meadows Water Authority Woods and Poole IHS – Global Insight
Washoe County Consensus Forecast
TMRPA Land Use Fabric Washoe County Parcels Existing Dwelling Units Final Maps Planned Unit Developm ents (PUDs) Tentative Maps (TMs) Tracking Current and Future Land Use WC Parcels Vacancy status Update DU and LU Class Update Final Maps PUDsTMs TMRPA LU Fabric Tracking residential development present and future potential Monthly Process for Updating Land Use Fabric
Spatial Allocation of Predicted Growth Translate time series projections to spatial allocation of housing units and employment Rule-based allocation model that uses an overall suitability score Parcel-based Dual-mode suitability model Population Employment Model results can be aggregated to any geography Traffic analysis zones Wastewater treatment facility service areas TMWA fee areas Etc.
TMRPA Housing Study – 4 Scenarios Extensive research and outreach on past housing trends (since 2000) and future outlooks on housing demand Evaluation of 4 housing growth scenarios that simulate different spatial and temporal patterns Scenario 1a Recent trends + Consensus Forecast Scenario 1b Recent trends + EDAWN EPIC Forecast Scenario 2a Compact development + Consensus Forecast Scenario 2b Compact development + EDAWN EPIC Forecast Learn more:
TMWA Total Water Use Coefficients Water use coefficients are taken directly from the TMWA Water Resource Plan Weighted Average gives more weight to hydrobasins that have more units or meters in them Water Usage (1,000 gal) Hydro-basin Annual Usage GMWS GMWS Meters MMW (per customer) MMW (per unit)* Multi-Family Units RMWS Single-Family Units E W Average Weighted Average *Assumes an average of 10 units per service
Methods – Water Demand Calculations Dwelling Unit Type Dwelling Units (Dwelling Units×Coefficient×Gal lons)÷365 days Total Water Demand (GPD) Single Family (weighted) 1 (1×149.9×1000)÷365 = 411 Multi-Family (weighted) 1(1×42.4×1000)÷365 = 116 Weighted Average FactorsStraight Average Factors Businesses Per Employee Businesses Per Employee Meters Per Business0.4862Meters Per Business Non-Residential (GMWS) Unit (Units×Coefficient×Gall ons)÷365 days Total Water Demand (GPD) Non-Residential (employee- weighted) 1 Employee (1employee×0.075×0.4 9)(469.67×1000) ÷365 = 47 Gallons Per Employee Residential Non - Residential We chose a weighted-average approach to reflect the impact that more dwelling units and/or employees have on the overall average of water demand or wastewater generation We are still in process to compare our modeled water demand with existing demand values from TMWA
TMWA Indoor Water Use Coefficients Water use coefficients are derived from billing records from Indoor usage only Winter months from December - March Weighted Average gives more weight to hydrobasins that have more units or meters in them Indoor Water Usage (1,000 gal) Hydro-basin Annual Indoor Usage GMWS GMWS Meters MMW (per customer) MMW (per unit)* Multi-Family Units RMWS Single-Family Units E W Average Weighted Average *Assumes an average of 10 units per service
Methods – Wastewater Generation Calculations Dwelling Unit Type Dwelling Units (Dwelling Units×Coefficient×Gal lons)÷365 days Total Wastewater Generation (GPD) Single Family (weighted) 1 (1×53.992×1000)÷365 = 148 Multi-Family (weighted) 1 (1×35.661×1000)÷365 = 98 Weighted Average FactorsStraight Average Factors Businesses Per Employee Businesses Per Employee Meters Per Business0.4862Meters Per Business Non-Residential (GMWS) Unit (Units×Coefficient×Gall ons)÷365 days Total Wastewater Generation (GPD) Non-Residential (employee- weighted) 1 Employee (1employee×0.075×0.4 9)(469.67×1000) ÷365 = 47 Gallons Per Employee Residential Non - Residential We chose a weighted-average approach to reflect the impact that more dwelling units and/or employees have on the overall average of water demand or wastewater generation Our initial calculations indicate that the weighted approaches had produced results more in line with observed flows
Regional Wastewater Generation – Validation with Observed (2015) Water Reclamation Facility (method) Total Wastewater Generation - Employee Factors Weighted (GPD) Average Day Annual Flow (GPD) TMWRF26,787,64026,330,000 STMWRF3,339,4013,000,000 RSWRF1,459,3021,400,000 CSWRF325,080297,000 LVWRF182,921260,000 Totals32,094,34431,287,000 Percentage of ADAF % Comparison Calculated Observed
Modeled Wastewater Generation – 5 Scenarios Scenario 1A Predicted Wastewater Generation (GPD) Scenario 2A Predicted Wastewater Generation (GPD) WRF WRF TMWRF1,676,9383,193,7914,851,3286,232,927TMWRF1,727,8973,303,3874,998,5436,455,611 STMWRF427,155899,3921,361,6891,798,665STMWRF385,541814,6031,266,5681,637,415 RSWRF279,546591,609938,9021,135,789RSWRF258,876483,545807,3471,020,746 LVWRF75,878228,011423,068499,504LVWRF42,728202,810399,827505,412 CSWRF35,12375,303193,845462,476CSWRF35,12364,677140,464229,209 Totals2,494,6404,988,1057,768,83210,129,362Total2,450,1654,869,0217,612,7499,848,394 Scenario 1B Predicted Wastewater Generation (GPD) Scenario 2B Predicted Wastewater Generation (GPD) WRF WRF TMWRF2,526,5024,325,9555,580,7216,198,728TMWRF2,656,0004,545,8285,836,8706,477,900 STMWRF803,6891,326,1181,724,7391,847,129STMWRF737,2661,207,6701,531,4251,621,047 RSWRF513,447893,1071,113,0551,157,483RSWRF387,441764,433990,3541,027,214 LVWRF206,365329,329489,186504,958LVWRF170,190313,543496,739513,169 CSWRF75,661255,382425,292454,366CSWRF76,583160,974219,522252,111 Total4,125,6647,129,8909,332,99310,162,665Total4,027,4806,992,4479,074,9109,891,442 Consensus Forecast Predicted Wastewater Generation (GPD) WRF TMWRF1,780,5113,303,0794,683,2565,776,5107,157,846 STMWRF392,505745,0361,156,4241,451,0151,906,712 RSWRF277,695507,381770,471899,6531,244,608 LVWRF76,145158,792389,012558,634815,367 CSWRF35,89694,07796,916128,329191,680 Totals2,562,7524,808,3657,096,0798,814,14111,316,212
Comparison – Scenario 1A vs. 2A 1A vs 2A TMWRFSTMWRFRSWRFLVWRFCSWRFTOTAL Scenario ,676,9381,727,897803,689385,541279,546258,87675,87842,72835,123 2,871,1742,450, ,193,7913,303,3871,326,118814,603591,609483,545228,011202,81075,30364,6775,414,8314,869, ,851,3284,998,5431,361,6891,266,568938,902807,347423,068399,827193,845140,4647,768,8327,612, ,232,9276,455,6111,798,6651,637,4151,135,7891,020,746499,504505,412462,476229,20910,129,3629,848,394
Conclusions These data are now available to assist Jim Smitherman with the update of the Regional Water Management Plan We have worked closely to ensure Jim’s needs are met and that planning efforts across the region are aligned We have the capacity to evaluate other scenarios and to conceptualize differences using other geographic boundaries (e.g. fee areas) Although this delivery marks the end of our interlocal agreement around scenario planning, this is not the end of our relationship We are committed to continued collaboration with water and wastewater staff to calibrate model assumptions and to evaluate alternate scenarios, especially as our regional outlook of the future changes Capability for online dissemination of these data (and other related data) via our GIS map viewer products Password protected access Some printing and map composition functionality Access to tabular data