CAPITAL INVESTMENTS | Wastewater
Sewer Collection System Evaluation
DESCRIPTION
| PROJECT ID: | S 20.0 |
| ESTIMATED COST: | $160,000 |
| ACTUAL COST: | $169,508.08* |
- Includes review of collection system plans, old reports, video records, staff interviews, and GIS records
- Hydraulic model will simulate flow patterns through collection system based on land use throughout city
- Findings will be summarized in evaluation report to identify system deficiencies
- Cost estimates for improvements will be included
* Addition of some additional sections of sewer main to be inspected with video equipment increased costs beyond the original estimate.
WHY IT’S NEEDED
The last collection system evaluation was completed in 1997 and since then the population has increased by about 10,000 people. Periodic evaluations of the system allow the City to better monitor trouble spots, identify deficiencies, and make accurate cost estimates for improvements.
Precipitation that falls in Hermiston becomes stormwater and is managed in several ways, including surface runoff into open bioswales, underground injection and drainage when sandy soils allow, and collection and pumping to Hermiston Irrigation District facilities. This complex system has had to keep up with City growth into new areas as environmental regulations have changed. In many cases, when bioswales and underground injection facilities are overwhelmed, the water ends up at old pump stations.
As the Sewer Collection System Evaluation is being done, it makes sense to develop a comprehensive inventory of stormwater systems to more efficiently manage this process in to the future.
PROJECT STATUS:
Complete
PROJECT MILESTONES
March 2020
Graphic Information System and data collection begins.
May 2020
Stormwater mapping added to project.
September 2020
Final draft delivered to City and DEQ for review.
February 2021
DEQ provides initial comments and City submits revisions for review.
March 2021
DEQ accepts final report.
April 2021
City adopts final plan.
LAST UPDATED: 05/26/21
