Stormwater Master Plan: Storm Sewer Capacity Study Washington Lee - - PowerPoint PPT Presentation

▶
stormwater master plan
SMART_READER_LITE
LIVE PREVIEW

Stormwater Master Plan: Storm Sewer Capacity Study Washington Lee - - PowerPoint PPT Presentation

Oct 26, 2022 107 likes •280 views

Stormwater Master Plan: Storm Sewer Capacity Study Washington Lee High School October 13, 2011 Department of Environmental Services Goals Reduce the risk of potential stormwater threats to public health, safety, and property Develop

slide-1
SLIDE 1

Department of Environmental Services

Stormwater Master Plan:

Storm Sewer Capacity Study

Washington Lee High School

October 13, 2011

slide-2
SLIDE 2

Department of Environmental Services

Goals

 Reduce the risk of potential

stormwater threats to public health, safety, and property

 Develop system models that can

assess the impacts of new development on system capacity

 Comply with State and Federal

stormwater and floodplain management regulations

slide-3
SLIDE 3

Storm sewer network

366 miles of storm sewers, ~ 10,000 catch basins Only 28.5 miles left of original 50 mile stream network

Original stream network

slide-4
SLIDE 4

Department of Environmental Services

Modeling Approach

Modeling pipes / box culverts 36 inches in diameter or larger Calibrating using June 2006 event

slide-5
SLIDE 5

Department of Environmental Services

slide-6
SLIDE 6

Department of Environmental Services

slide-7
SLIDE 7

Department of Environmental Services

slide-8
SLIDE 8

Approximate water level in basement

Department of Environmental Services

slide-9
SLIDE 9

Department of Environmental Services

slide-10
SLIDE 10

Department of Environmental Services

Design Storm

  • Storm drainage systems typically designed

for the 10-year event

  • Use the June 2006 for calibration / prioritization

(event of record – worst since Tropical Storm Agnes in 1972)

  • Evaluate appropriateness of the 10-year event

at locations without overland relief.

slide-11
SLIDE 11

Department of Environmental Services

10 year flow = 7,540 cfs

slide-12
SLIDE 12

Department of Environmental Services

Capacity Projects in Progress

24th St. N. at N. Sycamore St. John Marshall Drive and Lee Hwy. West Little Pimmit Run Phases I & II Spout Run

slide-13
SLIDE 13

Department of Environmental Services

Climate Change

slide-14
SLIDE 14

Department of Environmental Services

Impacts not associated with Capacity

  • Sea level rise (a separate analysis)
  • Wind damage
  • Increase in frequency of hurricanes

and tropical storms

  • Increases in snowfall
slide-15
SLIDE 15

Department of Environmental Services

Arlington’s consultants estimate increases in 10-year precipitation of approximately 3% by 2050, and approximately 8% by 2100

slide-16
SLIDE 16

Department of Environmental Services

Questions?