Watershed Management Plan - Mason County

Sub-basin Summaries
Appendix
A
South Shore Sub-basin
The South Shore sub-basin is located on a narrow strip of land along the
southern shore of Hood Canal. Technically part of WRIA 14, the South
Shore sub-basin is addressed in this document in order to consolidate
planning for areas bordering Hood Canal. The Planning Units of WRIA 14
and WRIA 16 executed a formal agreement that WRIA 16 would undertake
watershed planning (under RCW 90.82) for this sub-basin, an agreement
that was approved by the Department of Ecology. In WRIA 14, the South
Shore sub-basin is known as the North Mason or Upper Mason sub-basin.
The South Shore sub-basin has no major drainages, but contains many
small creeks including Twanoh Falls Creek, Twanoh Creek, Alderbrook
Creek, and Happy Hollow Creek, as well as some intermittent streams and
seeps.
The major communities in the sub-basin are Union on the west side and the
outskirts of Belfair on the east side. This narrow strip of land has the
highest population density of all of the sub-basins in WRIA 16 with
approximately 2,772 people living in the basin in 2000 (EnviroVision,
2003). It is important to note, however, that many of the sub-basin’s
residents are seasonal and the population can double during summer
months.
WATER QUANTITY
Total discharge of water from the South Shore sub-basin, including both
surface water (streamflow) and groundwater seepage to Hood Canal, is an
estimated 59,550 acre-feet per year (AF/yr), the lowest of any WRIA 16
sub-basin. Of this total, an estimated 1,705 AF/yr are allocated as surface
water and groundwater. Some amount of water is also consumed via
permit-exempt wells, but the consultants for the Level 1 Technical Assessment
were not able to estimate it due to lack of data (Golder Associates, 2003).
Table 9, below, summarizes the known information on water quantity in
the South Shore sub-basin.
Final Plan for County Adoption – May 11, 2006 page 87