Part 1 - City of Bonney Lake

Water System Description
Topography
Elevations within the service area range from approximately 100 feet to 710 feet above sea level.
However, most of the service area is located on top of the Lake Tapps plateau which is defined
by the White River on the east and north, the Puyallup River on the west, and Fennel Creek on
the South. The plateau is dominated by the Lake Tapps reservoir with a normal high water level
of 543 feet above sea level. Several other small lakes are located throughout the service area,
including Bonney Lake; Debra Jane Lake; Hidden Lake; Bowman Lake; Hille Lake; Kirtley
Lake; Crawford Lake; Prinz Basin; and Church Lake. There are also a number of wetlands and
small creeks throughout the service area. The side slopes of the plateau consist of steep grades
which range from 25 percent to 50 percent. The terrain on the plateau is undulating with
numerous depressions of lakes and former lake beds. Most of the undeveloped areas are heavily
forested. The largest transportation corridor within the City’s service area is State Route 410,
which runs east/west through the southern portion of the plateau.
Climate
The climate of the service area is typical Puget Sound area weather. Rainfall within the City’s
WSA is monitored on a monthly basis at two locations: Victor Falls Springs and Grainger
Springs. Average annual rainfall at these stations from 1997 through 2003 was 42.83 inches and
47.06 inches, respectively. Historically, the period July through September is the driest. For the
years 1998 through 2002, average rainfall at these two stations during the summer months of
July, August, and September was 0.83 inches per month. In addition, Western Regional Climate
Center maintains daily climate data for a station located in Buckley, which is east of Bonney
Lake. Their records date back to the year 1931 and show an average annual rainfall of 48.6
inches and an average of 1.81 inches per month for the summer months of July, August, and
September. In comparison, for the years 1998 through 2002, average rainfall at this station
during the summer months of July, August, and September was 1.06 inches per month, which is
slightly higher than the data from the City’s stations. For analysis purposes, the years 1998
through 2002 were picked because they corresponded to the recent years for which the City had
good telemetry data for the summer months and subsequently demand factors used in this report
were calculated. This weather data indicates that the last seven years have been drier than
historical so the demand factors calculated should be slightly conservative.
Water Service Area
The City provides water service to most of the Lake Tapps plateau. The water service area
includes the areas generally bounded by:
The top of the plateau on the west,
The Pierce/King County line on the north,
234 th Avenue East on the east, and
112 th Street East/Buckley Boulevard/Rhodes Lake Road on the south.
CITY OF BONNEY LAKE COMPREHENSIVE WATER SYSTEM PLAN 2-3 J:\DATA\BON\507-036\PLAN\WCPCHAPTER2.DOC