CITY OF PACIFICA
COUNCIL AGENDA SUMMARY REPORT
7/11/2022
1 SUBJECT:
Study Session regarding the 2022 Storm Drainage Master Plan RECOMMENDED ACTION:
Receive an informational presentation regarding a status update of the 2022 Storm Drainage Master Plan.
STAFF CONTACT:
Lawrence Henriquez, P.E., Associate Civil Engineer
(650) 738-3772
[email protected]
Sam Bautista, P.E., DPW Deputy Director
(650) 738-3771
[email protected]
Lisa Petersen, P.E., DPW Director
(650) 738-3770
[email protected]
BACKGROUND/DISCUSSION:
The purpose of this study session is for City Council to receive an informational presentation regarding a status update of the 2022 Storm Drainage Master Plan (Master Plan).
The City collects and disposes storm water runoff generated within the City service area through a system of gravity storm drains and open channels connecting to outfalls into the Pacific Ocean. The existing storm drain pipelines range from 4-inches to 120-inches in diameter. The City’s storm drainage infrastructure includes almost 56 miles of storm drainage lines, 8.7 miles of open channels, over 20 ocean outfalls, 12 distinct drainage basins, and two City-operated pump stations.
In 2012, the City hired Carollo Engineers of Walnut Creek to develop a Storm Drainage Master Plan (SDMP), which modeled the existing storm drainage system. Future growth was identified as a key factor for the construction of new storm drainage facilities to accommodate the increase of runoff. The 2012 SDMP Master Plan Report also proposed a long-term maintenance program inclusive of the new infrastructure storm drainage facilities when constructed. 2022 Storm Drainage Master Plan Update:
The reason for upgrading the 2012 SDMP was to address several key objectives such as:
• Industry standard recommendation for updating master plans every 10-15 years. • Updating the City’s hydrologic and hydraulic model that has since become outdated.
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• Serve future growth projected by active planning applications and General Plan update land use designations.
• Understand the potential impacts of climate change on the existing storm drainage system.
• Develop a prioritized capital improvement plan and identify potential funding options for transition into the construction phase.
• Document any deficient areas of the City to be addressed by the Master Plan. • Receive any public comments and input to incorporate into the updated plans.
Through a Request for Proposals and consultant interviews process, City staff chose Carollo Engineers to update the 2012 SDMP. Carollo Engineer’s scope of work included the above elements.
The 2022 SDMP efforts began by collecting existing data regarding the City’s storm drainage system during Summer 2021. In December 2021, flow meters were deployed at strategic locations throughout the City storm drain system in anticipation of forecasted rain events to capture flowrate data through the storm drain pipes. The flowrate data collected was used to calibrate and update the outdated hydrologic/hydraulic models to determine future capacity limitations for the City’s storm drainage system. This model assists in identifying deficient areas and helps the engineers determine what improvements could be designed and implemented.
City staff engaged in a stakeholder outreach program with the objective of securing community input regarding storm drainage matters. The first community outreach activity City staff participated in was through pop-up events held in October and November 2021 at the Pacifica Farmer’s Market in Rockaway Beach. Flyers distributed at the events contained information directing residents to the City’s developed Master Plan webpage to provide storm drainagerelated comments to help with development of the Master Plan. Staff was also at the pop-up events and responded to resident questions regarding the City’s storm drainage system.
The City also solicited public feedback through a dedicated page on the City’s website which provided Pacifica residents with an opportunity to share their issues with storm drainage in the City. The page was published on social media and residents were encouraged to provide feedback. The social media outreach included the City’s newsletter, Connect with Pacifica, Facebook and Nextdoor postings. Based on this outreach, the City received concerns/input from residents on a number of issues including:
1. Monterey Road Drainage Basin
a. Water ponding in street due to lack of inlets/inadequate inlet size b. Erosion/damage due to runoff on private property
c. Concerns about creek capacity in the “Big Inch”
d. Other maintenance concerns and improvements/repairs needed
2. East/West Sharp Park Drainage Basin
a. Issues with culvert and potential slope failure
3. Lower Linda Mar / Rockaway Beach Drainage Basin
a. Frequent ponding/flooding concerns on Montezuma and Anza/Arguello (Lower Linda Mar)
b. Small amount of runoff in street year-round from a localized naturally-occurring spring in the 600-block of Rockaway Beach Avenue
The community outreach activities provided existing condition information, which Carollo investigated to substantiate storm drainage infrastructure recommendations. The recommendations will be furnished to City Council at a future meeting relating to CIP projects and prioritization.
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July 11, 2022
Since the environment is evolving, the Master Plan will analyze the storm drainage system as it relates to climate change. There have been studies prepared by the National Oceanic and Atmospheric Association which discusses climate impact changes, such as sea level rise, coastal flooding, and erosion. A technical memorandum summarizing the findings and recommended considerations would be included in the Master Plan.
The next steps will be for City staff to bring the draft Master Plan with recommendations to Council at a future meeting to discuss the findings, which would include the Capital Improvement Program (CIP) projects and their prioritizations to help inform future year CIP recommendations for City Council approval. The Master Plan is tentatively scheduled for completion in September 2022.
ALTERNATIVE ACTION:
There are no alternative actions at this time.
RELATION TO CITY COUNCIL GOALS AND WORK PLAN:
The 2022 Storm Drainage Master Plan is consistent with the following Council adopted Goals:
• Stewardship of City Infrastructure: includes repairing/replacing outdated city facilities such as city hall, the libraries, fire stations, etc., improving streets, and responding to impacts of sea level rise. The 2022 Storm Water Master Plan will recommend areas in the City for improving stormwater drainage infrastructure while taking into account the effects of sea level rise
FISCAL IMPACT:
There is no fiscal impact as a direct result of this study session.
ORIGINATED BY:
Public Works
ATTACHMENT LIST: