1. Scenario Planning for Water and Wastewater in the Truckee Meadows
WRWC Agenda Item 9
Jeremy M. Smith, TMRPA
Jim Smitherman, WRWC
8/17/2016

2. 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

3. 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

4. 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

5. Washoe County Consensus Forecast

6. Washoe County Consensus Forecast

7. Tracking Current and Future Land Use
Tracking residential development present and future potential
Tracking employees by business location
TMRPA Land Use Fabric
Washoe County Parcels
Existing Dwelling Units
Final Maps
Planned Unit Developments (PUDs)
Tentative Maps (TMs)
Each month we download the most recent Washoe County Parcel data in order to update land use and dwelling unit counts. We are also able to digitized in (bubble map) parcels from lot block plans from Planned Unit Developments and Tentative Maps. Final maps are record straight from the assessor parcel data.
Monthly Process for Updating Land Use Fabric
WC Parcels
Vacancy status
Update DU and LU Class
Update Final Maps
PUDs
TMs
TMRPA LU Fabric

8. 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.

9. 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:

10. TMWA Total Water Use Coefficients
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 83
149.6 -
14.95 3
 149.6
213 85
326.9
206
360.0
36.0
944
162.0
17407 86
171.5 19
191.0
19.1
234
98.8
6079 87
632.3
5646
421.0
42.1
49501
144.5
78137
088E
351.6
35.2 8
258.7
2093
088W
301.5 89
375.8 33
368.7
1898 92
600.9
270
636.5
63.6
1231
110.4
11710
Average
365.5
193.9
Weighted Average
611.0
42.4
149.9
*Assumes an average of 10 units per service
We worked with Shawn Stoddard and Laine Christman to obtain TMWA indoor water use coefficients. GMWS represents commercial use while MMW represents multi-family and RMWS represents single family. We utilized the straight average which is the second row from the bottom and a weighted average which gives more weight to hydrobasins with more units in them. We then applied these coefficients to each parcel to calculate wastewater generation.
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

11. Methods – Water Demand Calculations
Residential
Non - Residential
Dwelling Unit Type
Dwelling Units
(Dwelling Units×Coefficient×Gallons)÷365 days
Total Water Demand (GPD)
Single Family (weighted) 1
(1×149.9×1000)÷365 =
411
Multi-Family (weighted)
(1×42.4×1000)÷365 =
116
Non-Residential (GMWS)
Unit
(Units×Coefficient×Gallons)÷365 days
Total Water Demand (GPD)
Non-Residential (employee- weighted)
1 Employee
(1employee×0.075×0.49)(611.0×1000) ÷365 =
62 Gallons Per Employee
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
This table shows the formulas that use the coefficients shown from the previous page. We used a straight average and a weighted average for each WRF. The weighted average for residential gives more weight to parcels with greater amounts of single family and multi-family units in them. The weighted average for industrial gives more weight to parcels with a greater number of businesses and employees on it.
Weighted Average Factors
Straight Average Factors
Businesses Per Employee
0.0750
Meters Per Business
0.4862
0.3578

12. TMWA Indoor Water Use Coefficients
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 83
170.4 - 3
213 85
265.8
206
325.1
32.5
944
51.5
17407 86
201.9 19
193.5
19.4
234
64.4
6079 87
481.5
5646
356.5
35.7
49501
55.4
78137
088E 8
36.0
2093
088W
116.2
30.5 89
101.6 33
24.0
1898 92
397.5
270
415.8
41.6
1231
55.3
11710
Average
247.8
322.7
32.3
45.3
Weighted Average
469.67
54.0
*Assumes an average of 10 units per service
We worked with Shawn Stoddard and Laine Christman to obtain TMWA indoor water use coefficients. GMWS represents commercial use while MMW represents multi-family and RMWS represents single family. We utilized the straight average which is the second row from the bottom and a weighted average which gives more weight to hydrobasins with more units in them. We then applied these coefficients to each parcel to calculate wastewater generation.
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

13. Methods – Wastewater Generation Calculations
Residential
Non - Residential
Dwelling Unit Type
Dwelling Units
(Dwelling Units×Coefficient×Gallons)÷365 days
Total Wastewater Generation (GPD)
Single Family (weighted) 1
(1×53.992×1000)÷365 =
148
Multi-Family (weighted)
(1×35.661×1000)÷365 = 98
Non-Residential (GMWS)
Unit
(Units×Coefficient×Gallons)÷365 days
Total Wastewater Generation (GPD)
Non-Residential (employee- weighted)
1 Employee
(1employee×0.075×0.49)(469.67×1000) ÷365 =
47 Gallons Per Employee
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
This table shows the formulas that use the coefficients shown from the previous page. We used a straight average and a weighted average for each WRF. The weighted average for residential gives more weight to parcels with greater amounts of single family and multi-family units in them. The weighted average for industrial gives more weight to parcels with a greater number of businesses and employees on it.
Weighted Average Factors
Straight Average Factors
Businesses Per Employee
0.0750
Meters Per Business
0.4862
0.3578

14. Regional Wastewater Generation – Validation with Observed (2015)
Calculated
Observed
Water Reclamation
Facility (method)
Total Wastewater Generation - Employee Factors Weighted (GPD)
Average Day
Annual Flow (GPD)
TMWRF
26,787,640
26,330,000
STMWRF
3,339,401
3,000,000
RSWRF
1,459,302
1,400,000
CSWRF
325,080
297,000
LVWRF
182,921
260,000
Totals
32,094,344
31,287,000
Comparison
Percentage of ADAF
102.58%

15. Modeled Wastewater Generation – 5 Scenarios
Scenario 1A
Predicted Wastewater Generation (GPD)
Scenario 2A
WRF
2020
2025
2030
2035
TMWRF
1,676,938
3,193,791
4,851,328
6,232,927
1,727,897
3,303,387
4,998,543
6,455,611
STMWRF
427,155
899,392
1,361,689
1,798,665
385,541
814,603
1,266,568
1,637,415
RSWRF
279,546
591,609
938,902
1,135,789
258,876
483,545
807,347
1,020,746
LVWRF
75,878
228,011
423,068
499,504
42,728
202,810
399,827
505,412
CSWRF
35,123
75,303
193,845
462,476
64,677
140,464
229,209
Totals
2,494,640
4,988,105
7,768,832
10,129,362
Total
2,450,165
4,869,021
7,612,749
9,848,394
Scenario 1B
Scenario 2B
2,526,502
4,325,955
5,580,721
6,198,728
2,656,000
4,545,828
5,836,870
6,477,900
803,689
1,326,118
1,724,739
1,847,129
737,266
1,207,670
1,531,425
1,621,047
513,447
893,107
1,113,055
1,157,483
387,441
764,433
990,354
1,027,214
206,365
329,329
489,186
504,958
170,190
313,543
496,739
513,169
75,661
255,382
425,292
454,366
76,583
160,974
219,522
252,111
4,125,664
7,129,890
9,332,993
10,162,665
4,027,480
6,992,447
9,074,910
9,891,442
Consensus Forecast
2040
1,780,511
3,303,079
4,683,256
5,776,510
7,157,846
392,505
745,036
1,156,424
1,451,015
1,906,712
277,695
507,381
770,471
899,653
1,244,608
76,145
158,792
389,012
558,634
815,367
35,896
94,077
96,916
128,329
191,680
2,562,752
4,808,365
7,096,079
8,814,141
11,316,212

16. Comparison – Scenario 1A vs. 2A
TMWRF
STMWRF
RSWRF
LVWRF
CSWRF
TOTAL
Scenario 1 2
2020
1,676,938
1,727,897
803,689
385,541
279,546
258,876
75,878
42,728
35,123
2,871,174
2,450,165
2025
3,193,791
3,303,387
1,326,118
814,603
591,609
483,545
228,011
202,810
75,303
64,677
5,414,831
4,869,021
2030
4,851,328
4,998,543
1,361,689
1,266,568
938,902
807,347
423,068
399,827
193,845
140,464
7,768,832
7,612,749
2035
6,232,927
6,455,611
1,798,665
1,637,415
1,135,789
1,020,746
499,504
505,412
462,476
229,209
10,129,362
9,848,394

18. 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

19. Questions?