Olympia Sea Level Rise Modeling

Client: City of Olympia Public Works, Olympia, WA

Clear Creek Solutions constructed a WWHM-SWMM model of the City of Olympia drainage systems impacted by a rise in sea levels and associated Puget Sound high tides.

Process and Solution

City GIS data was used to create SWMM models of the City of Olympia drainages that may be impacted by a rise in sea levels.

These SWMM models were first created in SWMM5.

Then they were imported into XPSWMM, a more complex and slower model, for refinements and analysis.

This approach allowed continuous analysis of the drainage system using the EXTRAN module of SWMM.

The model included as much detail about the drainage network as existed in the City GIS database.

The precipitation time series included data through December 10, 2007 was used to calibrate the models to recent events.

All known or observed water surface elevations were used in an effort to calibrate the model performance as best as possible.

While flow and stage data simply does not exist for these drainage systems, this approach was sufficient to analyze current and future scenarios.

Current and potential future tide scenarios were identified and added to the models.

The models were then run to identify potential drainage problem areas.

Potential implications to the LOTT Alliance wastewater treatment facility and combined sewer overflows were addressed.

The potential flooding recurrence interval and potential contributions to the combined system were computed.

Result

Clear Creek Solutions provided analysis and results for five scenarios. Each scenario was analyzed for the following:

  1. Flooding volume and duration for each of three different tidal conditions at the identified problem areas. The analysis defined the magnitude of the potential problems.
  2. Scenarios addressed implications to the LOTT facility. City and LOTT staff helped to define the significance of impacts to LOTT.
  3. Volume of flow into the combined system and interval of contribution.

Our Projects

Land Development Stormwater Analysis
Land Development Stormwater Analysis

A private client contracted with Clear Creek Solutions to investigate potential downstream flooding in conjunction with a proposed land development in Western Washington. The development will be constructed to provide direct discharge from the project site through a tide gate to Puget Sound.

Government Canal Stormwater Analysis Study
Government Canal Stormwater Analysis Study

The City of Pacific contracted Clear Creek Solutions as the stormwater modeling subconsultant to find a pump solution to alleviate flooding in and around the Government Canal.

Monte Villa Parkway Drainage Study
Monte Villa Parkway Drainage Study

The City of Bothell contracted Clear Creek Solutions to investigate the observed street and private property drainage problems along 35th Avenue SE between 228th Street SE and 240th Street SE and south of 240th Street SE to Monte Villa Parkway.

Yauger Park Regional Stormwater Facility Expansion
Yauger Park Regional Stormwater Facility Expansion

Clear Creek Solutions (CCS) and Davido Consulting Group (DCG) were selected by the City of Olympia to assist in the proposed expansion of a joint-use recreation and stormwater flow control facility.

Hydrologic And Hydraulic Modeling Of The Yauger Park Drainage Basin
Hydrologic And Hydraulic Modeling Of The Yauger Park Drainage Basin

The City of Olympia contracted with Clear Creek Solutions to provide hydrologic and hydraulic modeling services. Our solutions were successful in reducing flooding in the Yauger Park drainage system caused by large events like the December 2007 flood.

Edwards Aquifer Recharge Modeling
Edwards Aquifer Recharge Modeling

Comparative analyses were made to determine the preferred precipitation data set for the model.

Costco Stormwater Facility Sizing
Costco Stormwater Facility Sizing

Costco's development of a new store in south Snohomish County, just north of Woodinville, required innovative strategies and analysis to protect adjacent Little Bear Creek.

HSPF Watershed Calibration Clark County, WA
HSPF Watershed Calibration Clark County, WA

Clark County contracted with Otak to update the County's stormwater ordinance. Clear Creek Solutions was hired to produce HSPF calibrations of two watersheds in the county.

Olympia Sea Level Rise Modeling
Olympia Sea Level Rise Modeling

Clear Creek Solutions constructed a WWHM-SWMM model of the City of Olympia drainage systems impacted by a rise in sea levels and associated Puget Sound high tides.

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