WRIA 59 Water Bank Feasibility Study

Transcription

1 DRAFT WRIA 59 Water Bank Feasibility Study Water Bank Demand Evaluation December 31, 2014 Prepared for: Stevens County And WRIA 59 Watershed Management Board Prepared by: Water & Natural Resource Group, Inc. PO Box Spokane, WA And Stevens County Conservation District 232 Williams Lake Road Colville, WA Grant G Stevens County, WA December 31,

2 Introduction In the last 40 years, the population of Stevens County has more than doubled. The Colville River Watershed (WRIA 59) encompasses over 600,000 acres and contains many of the residents of the county. In 1977, Chapter WAC closed WRIA 59 to new surface water rights, except for seasonal, conditional water rights along the mainstem of the Colville River. From 1977 through the early 1990s, new groundwater rights were issued for those applications that were determined not to be in continuity with surface water. In 1994, the Washington State Supreme Court Postema Decision restricted issuance of new groundwater permits in those areas of the state with closed surface waters. Exempt wells were not affected by this decision but Washington Department of Ecology stopped issuing new groundwater rights in areas where surface waters had been closed to further appropriation within WRIA 59. In light of these actions concerning water rights, planning efforts for future water needs have been given a high priority by local watershed groups. One method of addressing future water needs is through the establishment of a water bank within the watershed to meet future water demands. This evaluation is designed to estimate future demand within the WRIA 59 subbasins that may interact with such a water bank. Specifically, and estimate of growth and potential future water needs was developed from readily available data for each of the subbasins in the Colville River Watershed. Summary There are 19 subbasins within the WRIA 59 Colville River Watershed as shown in Table 1. Seven are located in the upper watershed, seven in the middle, and five in the lower portion of the Colville Basin. Figure 1 presents a map of the watersheds within the basin. Table 1: Summary of Subbasins Located in WRIA 59 Watershed Upper Watershed Middle Watershed Lower Watershed Sheep Creek Colville River South Colville River North Deer Creek Sherwood Creek Gold Creek Grouse Creek Chewelah Creek Haller Creek Bulldog Creek Thomason Creek Mill Creek Cottonwood Creek Blue Creek Little Pend Oreille River Waitts Creek Stensgar Creek Huckleberry Creek Stranger Creek Some work has been conducted previously to estimate future water needs in WRIA 59 through the year In February 2013, the Stevens PUD (on behalf of the WRIA 59 WMG) contracted HDR to develop a water needs assessment for WRIA 59. This analysis developed estimated future water needs in the Upper, Middle, and Lower areas of the Colville River watershed (HDR, 2013). The information developed in the HDR Memo was used with additional analysis completed by the Stevens County Planning Department for permits issued in the past 10 years, and an analysis of the WRTS database for irrigation was used to develop the estimates presented within this report. December 31,

3 Figure 1: Map of WRIA 59 Showing Locations of Subbasins. December 31,

4 Four water use sectors were evaluated for potential future water needs in the WRIA 59 basin. These include: agricultural irrigation, municipal supply, domestic wells, and industrial uses. The HDR 2013 Memorandum estimated that if sufficient water is available, increases in consumptive uses within WRIA 59 would require approximately 9,800 additional acre feet (consumptive) in It should be noted that this is a rough estimate especially when considering the water needed for agricultural irrigation. Estimates for the irrigation category were provided by the WRIA 59 Watershed Implementation Team and local water resources consultants. There are no detailed records available for agricultural irrigation at this time. In the water needs assessment conducted for Stevens PUD, HDR used 7,000 acre feet of consumptive use to define agricultural irrigation. This is probably on the low end of the potential range of consumptive uses and was selected due to uncertainties that water use for agricultural irrigation will grow significantly in the future based upon current land use trends within Stevens County. For this analysis, In 2011, the Washington State Department of Ecology (Ecology) Office of Columbia River (OCR) completed their Long-Term Water Supply and Demand Forecast (Ecology, 2012a). The Forecast s purpose was to help OCR effectively plan and implement water supply projects by better understanding where additional water supply is currently needed, and where it will be needed in the future. Within the technical report that supported this Forecast (Ecology, 2012b), estimates of future water needs for each WRIA within the state were developed. Attachment A presents the summary for WRIA 59 (Ecology, 2012b). In summary, the findings of this report concluded that: In 2030, combined municipal and surface water irrigation demands and adopted instream flows are projected to outstrip unregulated tributary supply at the watershed scale during most years for August and September, and in some years for June, July and October. Additional water supplies may be available from the Columbia River in a localized area of the watershed. Modeling of curtailment of interruptible irrigation water rights indicated that it occurred 80% of years between 1977 and The resulting unmet demand ranged from 233 to 11,187 ac-ft per year depending on yearly flow conditions, with an average of 3,490 ac-ft per year. Simulation of future curtailment occurred in 93% for the 2030s middle climate scenario. The resulting unmet demand per year ranged from 783 to 12,829 with an average of 4,807 ac-ft per year. This report only looked at basin wide estimates and no delineation of unmet water demands at a subbasin level was conducted. The full 2011 Demand forecast can be found at: Current Water Right Applications The WNR Group conducted a search of the WRTS database to determine how many outstanding water right applications were present in the basin. The database showed that as of December 2014, there are 53 active water right applications for WRIA 59. Table 2 shows a summary of these applications in each of the subbasins. As shown on Table 2, the majority of water right applications are located on the main valley floor (Colville River North & South subbasins). The tributaries of Sheep Creek (5 applications), Huckleberry Creek (6 applications), and Little Pend Oreille River December 31,

5 (6 applications) are the tributaries in the Upper, Middle, and Lower Watershed areas, respectively, where additional water is currently being requested. An estimate of requested acre-feet per use per subbasin is presented in Table 3. As shown in Table 3, a total of AF of water is being requested in existing applications. Of this, agricultural irrigation is the largest quantity requested at AF (appx 78%) to irrigate approximately 1539 additional acres. Current applications on file with Ecology show that Waitts Creek (1002 AF), Sheep Creek (850 AF), Chewelah Creek (757 AF), Colville River North (697 AF) and Stranger Creek (608 AF) are the subbasins in which the largest quantity of acre-feet requested for all uses. The WRTS database for all water right applications in WRIA 59 per subbasin is presented in Attachment B. TABLE 2: WRIA 59 WRTS Database - Water Right Applications within WRIA 59 IRR IRR + other Requested Acres MU DM DS ST/ Dom PO Other Total Applications Upper Watershed Sheep Creek Deer Creek 2 2 Grouse Creek Bulldog Creek Cottonwood Creek 0 Waitts Creek Huckleberry Creek Middle Watershed Colville River South Sherwood Creek 0 Chewelah Creek Thomason Creek 0 Blue Creek 0 Stensgar Creek Stranger Creek Lower Watershed Colville River North Gold Creek 0 Haller Creek 0 Mill Creek Little Pend Oreille River TOTAL Note: Information as of December 2014 per Ecology WRTS Database December 31,

6 TABLE 3: WRIA 59 WRTS Database - Water Right Applications within WRIA 59 (EST. ACRE-FEET) Estimates provided in Acre-Feet IRR MU DM DS ST/Dom Stock Other Total AF Requested Upper Watershed Sheep Creek Deer Creek Grouse Creek Bulldog Creek Cottonwood Creek 0.0 Waitts Creek Huckleberry Creek Middle Watershed Colville River South Sherwood Creek 0.0 Chewelah Creek Thomason Creek 0.0 Blue Creek 0.0 Stensgar Creek Stranger Creek Lower Watershed Colville River North Gold Creek 0.0 Haller Creek 0.0 Mill Creek Little Pend Oreille River Notes: TOTAL Acre footage for irrigation = 2.5 feet/acre Some MU water right applications were only requesting additional Qi, and no Qa DM - application was assuming a small water system of 5,000 gpd (5.6 AF/yr) Stock request was estimated at 1.0 AF/yr ST/Dom was estimated at 2.0 AF/yr Power generation and Fish Rearing applications were considered non-consumptive Water Needs for Irrigated Agriculture (From HDR Water Needs Assessment for WRIA 59) The WRIA 59 Watershed Plan addressed potential expansion of irrigated lands within the Colville River Basin. The plan indicated that the basin had approximately 7,200 acres of irrigated farm land in Based on a review of previous applications for expansion of irrigated farmland, the plan concluded that approximately 2,760 acres of new irrigated land could be expected by 2025, if water were available. This represents a 38% increase over irrigated lands in The plan also indicated that a typical water duty for farmland in the Colville River Basin is 3.0 acre-feet (AF) per acre of irrigated land, but that this water duty could be expected to go down in future years due to increased efficiencies in new irrigation systems and the needs of the typical crops grown in WRIA 59. A water duty of 2.0 acre-feet per acre was recommended for assessment of future agricultural irrigation needs. However, Ecology has reportedly been using 2.5 acre-feet per acre in recent evaluations of water use in the Basin. December 31,

7 Information compiled for the watershed plan was used by the U.S. Geological Survey (Kahle et al. 2003) to assess irrigation uses of water. Irrigated crops in the basin consist primarily of alfalfa grass and small grains, with some corn and potatoes. The acreages listed above for existing farmland were combined with a water duty of 3.0 acre-feet per acre, to yield an estimated usage in 2002 of 21,570 acre-feet per year for agricultural irrigation. Based on descriptions of typical irrigation practices in the Colville River Basin provided by Stevens County staff, there is minimal return flow of irrigation diversions to surface waters. While there may be some water that passes through the root zone and enters shallow aquifers in the basin, Kahle et al did not identify any return flow from irrigation uses. Therefore, in this analysis, it is assumed that return flow from irrigated farm land to surface and groundwater is negligible. Using the estimate of 2,760 acres of new irrigated farm land from the Watershed Plan, and a water duty of 2.5 acre-feet per acre, yields an increase of 6,900 acre-feet in consumptive irrigation usage for the basin (see Table 4, below). The table is broken down into the upper, middle and lower basins, using the same acreage breakdown listed by Kahle et al. (2003). The data shown in Table 2 assumes increases in irrigated acreage will be spread out from 2010 to Actual changes could occur on a different schedule, and the consideration of alternative water supply and management solutions should provide flexibility in terms of the timing of increases in water need. Table 4: Irrigated Acreage and Associated Water Use, (HDR, 2013) Changes from to 2050 Estimated Irrigated Land (Acres) Upper Basin 2,800 3,145 3, Middle Basin 1,200 1,614 2, Lower Basin 3,190 3,811 4,432 1,242 Total Land Area 7,190 8,570 9,950 2,760 Estimated Water Use (Acre Feet) Upper Basin 8,400 9,263 10,125 1,725 Middle Basin 3,600 4,635 5,670 2,070 Lower Basin 9,570 11,123 12,675 3,105 Estimated Total Water Use 21,570 25,020 28,470 6,900 In Table 4, for estimated irrigated land, the Watershed Plan allocated 25% of the estimated increase (2760 acres) in each decade from 2012 to For estimated water use, and application of 3.0 acre-feet per acre was used through 2012 and 2.5 acre-feet per acre was used for the future. It is assumed that 100% of irrigation usage is consumptive. Future water needs for agricultural uses was also analyzed for this project. An analysis of the Water Rights Tracking System (WRTS) was conducted by WNR Group to estimate amount of existing irrigated land in each of the 19 subbasins was authorized by State water right certificates. Table 5 shows the approved acres and acre-feet in each of the subbasins, and Figure 2 presents the December 31,

8 results in a graph. It should be noted that although the agricultural water rights are listed within the WRTS database, it does not necessarily mean that they are currently being use, or as a result of non-use have been relinquished in accordance with RCW In addition to the WRTS database, the WNR Group reviewed the data developed from the FSA. This data estimates the amount of farm acreage currently being used in the watershed at 10,913 acres. Using an assumed 5% growth per decade of irrigated acres, if water was available, Table 6 presents an estimate of potential irrigation future demands for irrigation in each of the subbasins of WRIA 59. TABLE 5: Summary of WRTS Database showing Certificated Acres and AF for each subbasin in WRIA 59 Subbasin Acres Acre-Feet Sheep Creek Deer Creek Grouse Creek Bulldog Creek Cottonwood Creek Waitts Creek Huckleberry Creek Colville River South Sherwood Creek Chewelah Creek Thomason Creek Blue Creek Stensgar Creek Stranger Creek Colville River North Gold Creek Haller Creek Mill Creek Little Pend Oreille River TOTAL December 31,

9 TABLE 6: Summary of FSA Database showing Estimated Irrigated Acres for each subbasin in WRIA 59 No. Irr. Properties 2013 FSA Estimate 2013 Estimated Projected Need 2030 Estimated Projected Need 2050 Total Acres & AF Used by 2050 Subbasin Acres Acre-Feet Acres Acre-Feet Acres Acre- Feet Acres Acre-Feet UPPER BASIN Sheep Creek , , ,816.2 Deer Creek Grouse Creek Bulldog Creek Cottonwood Creek Waitts Creek Huckleberry Creek MIDDLE BASIN Colville River South , , ,016.4 Sherwood Creek Chewelah Creek Thomason Creek ,168.7 Blue Creek Stensgar Creek Stranger Creek , ,001.4 LOWER BASIN Colville River North 58 1, , , , ,038.5 Gold Creek Haller Creek Mill Creek 64 1, , , , ,639.6 Little Pend Oreille River TOTAL 270 6, , , , , , , ,087.5 Projected needs assume an inferred growth of approximately 2760 additional irrigated acres in basin by year 2050, or an approximate growth of 75 acres/year and AF/year within WRIA 59. December 31,

10 Distribution of Acres & AF Per WRIA 59 Subbasin Acres Acre-Feet FIGURE 2: Presentation of acres and acre-feet as documented from WRTS database. Water Needs for Municipal Systems There are several Group A water systems in WRIA 59. Stevens PUD supplies water for several community systems as shown in Table 7, and there are 4 municipalities that provide water within defined service areas: Kettle Falls, Colville, Chewelah, and Springdale (listed downstream to upstream). The water supply systems are: Upper Basin: Springdale and PUD systems Loon Lake, Waitts Lake, Deer Lake, Jump Off Joe, and Valley Middle Basin: Chewelah and PUD system at Addy Lower Basin: Colville, Kettle Falls, PUD systems Echo Estates, Dolomite, and Mission Ridge Table 7: Stevens PUD systems in WRIA 59 System Subwatershed Certificate # Current Connections Addy Colville River N 00367J Echo Estates Mill Creek Valley Colville River S 55520F Jump Off Joe Bulldog Creek 37165T Loon Lake Sheep Creek Waitts Lake Waitts Creek Deer Lake Grouse Creek 93380X Dolomite LPOR 29808T Mission Ridge Mill Creek 30434E Approved Connections December 31,

11 Except for the Jump Off Joe system, it appears that Stevens PUD has the capability of dealing with growth in its service areas. Table 8 presents a summary of the population and expected growth for the four municipalities in WRIA 59. Table 9 presents a summary of the water right status for each of these municipalities. Comparing the results of Tables 8 and 9, it would appear that the municipalities in WRIA 59 will be able to meet future growth needs. The four municipalities in WRIA 59 have been proactive in acquiring water rights to meet 20 year growth projections. Table 8: Projected growth of WRIA 59 Municipalities Chewelah Colville Kettle Falls Springdale 2014 population 2,615 4,690 1, % avg. growth per year from OFM Increase in Population by New residences assuming 2.44 people per residence from US Census Bureau Table 9: Municipal Water Systems WRIA 59 System Subwatershed Certificate # Current Connections Approved Connections Chewelah South Colville River S 12750B 1270 Recently acquired 129 AF so able to meet new growth Chewelah North Colville River S Colville Colville River N Writing new water system plan; sufficient water to meet growth needs Kettle Falls Colville River N Springdale Sheep Creek 83400Y In summary, municipalities within WRIA 59 appear to have sufficient quantities of certificated water for growth through Water Use for domestic Wells A considerable number of residences in WRIA 59 are on individual household wells and fall under a water right permit exemption. Private permit exempt wells are not metered so there are no definitive figures on water use from such systems. USGS in their study of groundwater system in WRIA 59 used estimates developed by the WRIA 59 Watershed Planning Team for 1998through It was estimated that 2,970 homes were served by permit exempt wells and these households December 31,

12 used approximately 600 gallons per day. This figure was derived from data from metered group water systems and was adjusted to reflect larger sized rural lots. In 2012, Stevens PUD performed an updated analysis of daily household water use for houses on wells. Again taking into consideration larger rural lots, PUD estimated a quantity of 350 gallons per day for household use. The Stevens County Planning Department reviewed building permits issued in the County for 2001 through Table 10 presents a summary of this analysis. As shown in Table 10, approximately 52% of the growth of rural domestic homes are occurring in the lower portion of the basin. Approximately 24% is occurring in each of the middle and upper portions of the basin. The largest expected domestic growth is to occur in the Colville River North subbasin (appx. 17 homes/yr), LOPR subbasin (appx. 11 homes/yr), Sheep Creek subbasin (appx. 9 homes/yr), and Mill Creek subbasin (appx. 9 homes/yr). To estimate the expected future demand, the average permit issued per subbasin was multiplied by an estimated future demand of 350 gpd/permit (0.392 AF/yr). Consumptive use of rural homes was estimated at 40% of average use (or 140 gpd) as determined by the Stevens PUD in 2012 of its metered systems. Table 10 presents the estimated additional AF per year, and estimated future needs in 2030 (225 AF) and 2050 (476 AF) for rural domestic homes above that being used in While not all permits involve permit exempt wells, the above table provides an indication of where potential growth is likely to occur. The HDR report (HDR 2013) took a different approach to determine future residential needs and estimated that the annual population growth for domestic well users in WRIA 59 from 2013 to 2020 will be 0.5% and from 2020 to 2050 it will be 0.75%. Based upon these assumptions, Table 11 presents HDR s anticipated water use for domestic wells. HDR estimated that an additional 157 AF would be needed for domestic uses by 2050, approximately 33% of the analysis conducted for this study using permit trends. December 31,

13 Sub-Basin Upper Watershed TABLE 10: WRIA 59 Residential Permits Total Est. Est. AF Avg. Permits Additional Need in Permits/Yr AF/Yr 2030 Est. AF Need in 2050 Sheep Creek Deer Creek Grouse Creek Bulldog Creek Cottonwood Creek Waitts Creek Huckleberry Creek Middle Watershed Colville River South Sherwood Creek Chewelah Creek Thomason Creek Blue Creek Stensgar Creek Stranger Creek Lower Watershed Colville River North Gold Creek Haller Creek Mill Creek Little Pend Oreille River Total Table 11: Predicted Water Use from Permit Exempt Wells in WRIA 59 (HDR, 2013) Change 2010 to 2050 Estimated population served by domestic 8,610 9,710 11,270 2,660 wells Estimated households served 3,210 3,620 4,210 1,000 Water use per household; gallons per day Estimated water use, gallons per day 1,123,500 1,267,000 1,473, ,000 % Consumptive use Estimated consumptive use in gallons per 449, , , ,000 day Estimated consumptive use in acre feet per year December 31,

14 The estimated population served by exempt wells was also estimated by USGS based upon OFM growth figures and the assumption that rural growth in WRIA 59 will be twice the urban growth. USGS also used 2.68 persons per household to determine the number of households served based upon 2000 census data. As stated previously, the 350 gallons per household per day is based upon analysis conducted by Stevens PUD. The percent of consumptive use was based upon analysis by Stevens PUD of its metered systems and adjusted for a rural environment. Water needs for Industrial Production Northwest Alloys in Addy was a large industrial operation that operated from 1976 to 2001 and was permitted to use 2,420 acre feet of water annually with an instantaneous rate of use of up to 1,500 gallons per minute. The operation is currently shut down. Boise Cascade operates 3 mills in the watershed that have use water for industrial purposes. The Avista waste-to-energy operation at Kettle Falls is expected to change its water source to a production well located in WRIA 61. Projected needs for future industrial growth is difficult to estimate. The HDR 2013 Memorandum estimated that an additional 2400 acre-feet of water would be required for industrial uses, or approximately 60 AF/year. In order to estimate potential needs per subbasin, the commercial and industrial permits issued by the County were reviewed for 2001 through 2012, and an average annual number of permits per subbasin was developed. The percentage per subbasins of total annual permits was then multiplies by the estimated 60 AF/yr of commercial and industrial growth, to determine an estimated potential growth per subbasin. Table 12 presents the results of this analysis and the estimated water needs per subbasin for the industrial and commercial sector. There are currently two former industrial water rights located within WRIA 59 which may be future growth areas for the county. These include the former Alcoa (Northwest Alloys) site located within the Stensgar Creek subbasin and the Northwest Magnesite Plant located in the Colville River South subbasin. The Northwest Alloys facility currently has two water right certificates on file (G and G ) which total 2,420 acre-feet and 1500 gpm. This site has been sitting idle for over 12 years. The site also owns two reservoir permits for 38 acre-feet (R ) and 28 acre-feet (R ). The Northwest Magnesite Plant has three certificates associated with the facility. These certificates allow a withdrawal of 240 gpm to withdraw 320 acre-feet. The Northwest Alloys and Northwest Magnesite Plant sites are located in the central area of the watershed. Stevens County would like to attract one or more new industrial companies to these sites that would have comparable water needs. If new industrial activities are developed at these sites, the existing water right certificates may have to be replaced with future water demand. December 31,

15 TABLE 12: WRIA 59 Industrial Permits and Estimated Future Industrial Needs Total Avg. Est. Est. AF Est. AF % of Sub-Basin Permits Permits/ Additional Need in Need in Permits Yr AF/Yr Upper Watershed Sheep Creek Deer Creek Grouse Creek Bulldog Creek Cottonwood Creek Waitts Creek Huckleberry Creek Middle Watershed Colville River South Sherwood Creek Chewelah Creek Thomason Creek Blue Creek Stensgar Creek Stranger Creek Lower Watershed Colville River North Gold Creek Haller Creek Mill Creek Little Pend Oreille River Total Estimated Future Total Water Use HDR 2013 summarized the projected water needs within WRIA 59 to the year The estimated total increase in consumptive use was estimated at 9,800 acre feet per year. HDR estimated that this number could range from 4,600 acre feet per year to as high as 12,800 acre feet per year, with 9,800 acre feet used as an estimated mean future demand. There is a certain amount of uncertainty in this HDR estimate due to data gaps in agricultural uses. HDR assumed an increase in irrigated acreage while to those involved with the agricultural community, there appears to be a decline in agriculture throughout the county in general and within WRIA 59 in particular. The following table was derived for the HDR water needs assessment. December 31,

16 Table 13: Summary of WRIA 59 water needs (HDR, 2013) change Withdrawals (acre-feet) Agricultural Use 21,570 25,020 28,470 6,900 Municipal Use 4,145 5,376 6,207 2,061 Domestic Use 1,258 1,419 1, Self-supplied Industrial Use 92 2,492 2,492 2,400 Total Withdrawals 27,066 34,307 38,819 11,753 Consumptive Use (acre-feet) Agricultural Use 21,570 25,020 28,470 6,900 Municipal Use 1,658 2,150 2, Domestic Use Self-supplied Industrial Use 83 2,003 2,003 1,920 Total Consumptive Use 23,814 29,741 33,616 9,801 In summary, the consumptive uses for future needs listed in Table 13 (HDR, 2013) can be broken down by basin as follows: Upper Basin 1,831 acre-feet Middle Basin 4,320 acre-feet Lower Basin 3,650 acre-feet Total 9,801 acre-feet Utilizing the different approach from averaging past Stevens County permits, Table 14 presents the estimated water needs per sector in each of the subbasins as developed under this analysis. In order to determine the potential water needs per subbasin, the following future needs estimates were used: Agricultural: Amount estimated from 2012 WSDA data using an estimated 5% growth per decade. Municipality: Amount estimated from review of existing water rights and discussions with water purveyors who relayed that they do not need additional water rights, Domestic: Amount estimated from using average annual domestic permits issued from 2001 through 2012, and projecting that average through Commercial/Industrial: Amount estimated from using average annual commercial/industrial permits issued from 2001 through 2012, with an estimated increase of 60 AF/yr, and projecting that average through Table 14 also lists the current water applications within the WRTS database to exhibit which subbasins could have growth in the immediate near future should water become available and pending applications processed. December 31,

17 Sub-Basin Total WR Application Request TABLE 14: Estimated Future Needs per Subbasin Est Municipal Domestic Industrial Agricultural Needed AF/yr Use AF/yr Use AF/yr Use AF/yr AF/yr Est. AF Need in 2030 Est. AF Need in 2050 EST. AF Needed in Applications Upper Watershed Sheep Creek , , Deer Creek Grouse Creek Bulldog Creek Cottonwood Creek Waitts Creek , Huckleberry Creek Middle Watershed Colville River South , , Sherwood Creek Chewelah Creek , Thomason Creek Blue Creek Stensgar Creek Stranger Creek , Lower Watershed Colville River North , , , Gold Creek Haller Creek Mill Creek , , LPOR Total , , , December 31,

18 CONCLUSION WRIA 59 has the potential for future growth in three market sectors: agricultural, industrial, and domestic exempt water needs. Review of current municipalities records indicates that the water purveyors have sufficient water rights for projected growth. Table 15 presents a list of the subbasins in order of priority for their potential future needs. It should also be noted that an additional 2,420 acre-feet may be needed in the Stensgar Creek subbasin to replace the Northwest Alloys water right, and an additional 320 acre-feet in the Colville River South subbasin to replace the NW Magnesite water rights. As shown in Table 15, future industrial and agricultural needs will be the priority for future water needs in the Colville River watershed. Sub-Basin Table 15: Estimates of Future Water Demands in WRIA 59 Subbasins Domestic Industrial Est Municipal Agricultural Use Use Needed AF/yr Use AF/yr AF/yr AF/yr AF/yr Est. AF Need in 2030 Est. AF Need in 2050 Colville River North , , Mill Creek , Colville River South , Sheep Creek , Stranger Creek LPOR Bulldog Creek Thomason Creek Chewelah Creek Stensgar Creek Waitts Creek Grouse Creek Deer Creek Haller Creek Sherwood Creek Cottonwood Creek Huckleberry Creek Blue Creek Gold Creek Total , , Note: an additional 2,420 acre-feet may be needed in the Stensgar Creek subbasin to replace the Northwest Alloys water right, and an additional 320 acre-feet in the Colville River South subbasin to replace the NW Magnesite water rights for future industrial needs. December 31,

19 References: Ecology, 2012(a): 2011Washington State Legislative Report: Columbia River Basin Long-Term Water Supply and Demand Forecast, Washington State Department of Ecology Publication No , 204 pp. Ecology, 2012(b): 2011 Technical Report for the Columbia River Basin Long-Term Water Supply and Demand Forecast, Washington State Department of Ecology Publication No , 452 pp. HDR, February 25, 2013, Water Needs Assessment for WRIA 59; Technical Memorandum prepared for the Stevens County Public Utility District (on behalf of WRIA 59 WMG). Stevens County Planning, 2014, unpublished permit database for industrial and domestic homes. December 31,