Project: Lower Monumental 1:55-Scale General Model
PI: Deborah Cooper
Branch/Group: Inland Hydraulic Structures Branch, Structures and Channels Group
Project Description/Activities/Capabilities:
Lower Monumental Dam 1:55-scale physical general model investigating performance of
deflectors, stilling basin, and tailwater, and entrainment flows.
Sponsor: Walla Walla District. POC Dan Katz
CHL Personnel
Deborah Cooper, Robert Bryant, James Cessna
Project Location and Description:
Lower Monumental Dam is located at River Mile 41.6 on the Snake River in Franklin and Walla
Walla Counties, Washington. The dam is about 3800 feet long and includes a powerhouse,
spillway, navigation lock, and two fish ladders (Figure 1). The powerhouse is on the north end of
the dam and consists of six Kaplan turbines, each with a 135,000-kilowatt generator. Maximum
discharge through the powerhouse is approximately 120 kcfs. The spillway is 512 feet long and
has eight 50 ft-wide by 60 ft-high tainter gates. The spillway crest is at elevation 483.0 with a
normal pool elevation of 540.0.
Facilities: Bldg. 3050
Related Topic Areas: Physical models, flow deflectors, dissolved gas, entrainment flow, rivers,
reservoirs, hydraulic structures, fish passage, surface water, hydropower, debris movement