Water Use In Whatcom County: 2010 Data, Estimates, Assumptions¹

Eric Hirst moved to Bellingham in 2002. He has a Ph.D. in engineering from Stanford University, taught at Tuskegee Institute (a black college in Alabama) for two years, and then for 30 years worked at the Oak Ridge National Laboratory as a policy analyst on energy efficiency and the structure of the electricity industry. Eric spent the last eight years of his career as a consultant.

It may be hard to believe, given how long and wet our rainy season is, but Whatcom County has serious water problems. This year’s very low snowpack and forecasts of drought this summer emphasize this reality.

Estimated Water Use in Whatcom County

Whatcom County water use in 2010 was almost 33 billion gallons/year (90 million gallons/day); see two tables below and figure 1 below them. Slightly more than half (57 percent) of the water is from surface water, and the remaining 43 percent is from groundwater (wells). Irrigation is, by far, the largest water use, accounting for 38 percent of the annual total. Industrial use accounts for 26 percent; homes for 22 percent; livestock for four percent; and aquaculture, mining and commercial account for the remaining 10 percent.

Because Whatcom’s water problems occur during the summer months, when usage is high and precipitation is low, it is useful to divide these annual totals into three seasons: summer (July, August and September); winter (November, December and January);2 and the other six months. The three summer months account for almost half the annual total, compared with only 13 percent for the three winter months. That is, summer water use is 3.6 times greater than winter use. For the Lower Nooksack portion of the county, summer water use is almost nine times greater than winter use (Fig. 2).³

Agriculture’s share of the total is much greater in the summer than year round: 65 percent vs. 42 percent, with irrigation accounting for 63 percentage points of the 65 percent summer share.⁴

Where Do These Numbers Come From?⁵

The key challenge in estimating local water use is the lack of metering for many water consumers. In particular, many (perhaps most) farms and rural homes are not metered. Even if their usage is metered, the results are not recorded on a regular basis and are not publicly available.⁶

The primary source for the annual figures is the U.S. Geological Survey (USGS), which estimated water use for 2005⁷ and 2010.⁸ Because of changes in data definitions, quality, and comprehensiveness between these years, I am not able to show how Whatcom water-use allocations and trends changed over time.⁹

The USGS report does not estimate commercial water use because of difficulty in collecting the data, primarily because there is no clear definition of what users should be in the category¹⁰ (e.g., motels, hotels, restaurants, office buildings, retail, and institutions). I estimated commercial-sector water use by calculating the ratio of commercial use to population for Bellingham and Lynden and then scaling the combined total up for the total county population. This calculation assumes that (1) commercial water use is proportional to population and (2) that this ratio holds throughout Whatcom County. ¹¹

Whatcom Farm Friends (WFF) estimated agricultural water use by month for Berries, Dairy, and Other.¹² The WFF numbers are based on estimates of monthly water use by crop.¹³ Livestock water use (primarily for cows) “includes water used directly by and for livestock, while water used to grow hay and other cattle feed is included in the Irrigation category.”¹⁴ I also obtained electricity-use data for Whatcom County irrigators (Schedule 29) from Puget Sound Energy (PSE). Figure 3 compares the monthly variation in irrigation water use from these two sources. ¹⁵

Because metered data are not available for agricultural water use, I used the USGS annual total and the WFF/PSE allocations to calculate irrigation numbers for the three seasons.

I used several sources to allocate annual water use to the three seasons. I used monthly data from Bellingham and Lynden to calculate the percentages of residential and commercial consumption for each month and then aggregated the monthly numbers to the three seasons.¹⁶ I used monthly data from PUD #1 on its industrial users (primarily the three large facilities at Cherry Point) and data from Bellingham and Lynden to do calculations for the industrial sector similar to those described for residential and commercial uses.

Conclusions

Agriculture, especially irrigation, dominates Whatcom water use, especially during the critical summer months. Irrigation accounts for almost two-thirds of summer water use. Other estimates (discussed above) are even higher.

Estimating Whatcom water use is challenging because so much usage is not metered, recorded, or reported and because the definitions, comprehensiveness, and accuracy of data sources vary over time. Resolving local water issues requires more complete, better defined and accurate data on water use to measure changes over time because of efficiency improvements and to allocate water to instream and out-of-stream uses.

Endnotes

1. I thank Tom Buroker, Randy Honcoop, Jon Hutchings, Steve Jilk, Skip Richards, and Gary Stoyka for their very helpful comments on earlier drafts of this paper. I thank Ron Lane for his help in interpreting U.S. Geological Survey estimates of water uses in 2005 and 2010.

2. I define the three winter months as those with the highest precipitation and the summer months as those with the lowest precipitation (and also highest water use).

3. C. Bandaragoda, “Lower Nooksack Water Budget,” p. 15, presentation to Whatcom County Natural Resources Committee, Sept. 11, 2012.

4. Irrigation accounts for 85 percent of July use in the Lower Nooksack Subbasin (237 cfs of 278 cfs total) (C. Bandaragoda et al., Lower Nooksack Water Budget Overview, Whatcom County, WRIA 1 Joint Board, 2012, p. 23). According to the Washington Dept. of Ecology, 87 percent of the growing-season Whatcom water use is for irrigation (Dept. of Ecology, Permit-Exempt Domestic Well Use in Washington, Final Draft, Nov. 2014).

5. I am glad to share the Excel workbook I created to produce these 2005 and 2010 numbers with anyone who would like to check these calculations and assumptions.

6. According to J. Greenberg, Chapter 7 of Lower Nooksack Water Budget Project, Dec. 2012 “measured diversion or withdrawal records are not available” for most agricultural water use. According to C. Bandaragoda et al., WRIA 1 Groundwater Data Assessment: Overview, June 2013, “the sources of [irrigation] water (ground and/or surface) are not readily known; nor are the locations from which it is withdrawn and where it is spread or applied to the land.”

7. R.C. Lane, Estimated Water Use in Washington, 2005, U.S. Geological Survey, No. 2009-5128, 2009.

8. M.A. Maupin et al., Estimated Use of Water in the United States in 2010, Circ. 1405, 2014. See http://water.usgs.gov/watuse/data/2010 for county-level details.

9. As examples, the 2005 database included industrial water supplied by water purveyors, but the 2010 database did not (Whatcom County PUD #1 supplied 13.5 million gallons/day to the large industries at Cherry Point in 2010); the Bellingham population was misreported for 2010; and the 2005 Washington Dept. of Health database included only 16 of 105 public water-supply systems, while the 2010 database included 85 systems. These and other anomalies and problems are explained in emails from Ron Lane, USGS, Jan. 16 and 26, 2015.

10. Email from Ron Lane, USGS, June 30, 2014.

11. These assumptions have little effect on results because the two cities account for 51 percent of the county’s population and because commercial water use is only about 6 percent of the annual total and 4 percent of the summer total.

12. Henry Bierlink, personal communication, Whatcom Farm Friends, July 2, 2014.

13. These estimates of monthly water use per acre are available for two locations in Whatcom County (Bellingham and Blaine) for 23 crops (Natural Resources Conservation Service, National Engineering Handbook: Irrigation Guide, U.S. Dept. of Agriculture, September 1997. Appendix A - Climatic Stations for Consumptive Use 1985).

14. Email from Ron Lane, USGS, Nov. 21, 2014.

15. Actual water use will differ from these estimates because of weather variations (e.g., rainfall and temperature), type and capacity of irrigation system, and farmer maintenance and operation of irrigation systems.

16. Rural households averaged 263 gallons/day (gpd), Lynden households 166 gpd, and Bellingham metered households 151 gpd.