The City of Coronado is reviewing its emergency response plan in anticipation of a forecasted El Niño weather event, which may bring record storms and rain.
In recognizing the possibility of flooding from El Niño, Coronado is taking precautions in advance of what may be a number of strong storms this rainy season and is reviewing its existing flood control and storm drain infrastructure. The City’s plan addresses flood preparedness, a notification process, flood response, floodwater removal and a contingency strategy.
In preparing for El Niño, it is important to understand what the City is dealing with regard to its storm drain system. For a small city, Coronado has a surprisingly complex system to handle and drain storm water. Due to relatively flat conditions and circumstances brought on by the former Spanish Bight that was filled in 70 years ago, Coronado is crisscrossed with storm drain lines that carry storm water to the bay and ocean and sanitary sewer lines that transport sewage for further treatment. For the most part, the storm drain lines work with gravity. Some, however, require pumps to help drain the water. Parker Pump Station is located on Coronado Avenue. It is an underground three-story building that houses pumps for storm drains as well as the sanitary sewer system. There are seven pumps for the storm drain system at Parker Pump Station of varying size. The smaller pumps are used to divert storm water to the sanitary sewer system.
During rain events, the larger pumps take surface and high ground water in the Country Club area and transport it to the North Beach Ocean Outfall. This is no small feat because before it was filled, there was a body of water called the Spanish Bight, which separated North Island from Coronado (see photo at right courtesy of: Coronado Historical Association). The waterway was 1½ football fields wide and the only connection was a 60-yard-wide strip of sand at high tide along the ocean side. This is important to note because that waterway now sits under the City’s Country Club area. Drainage problems abound in this area, which was filled in 1945 with structural fill, to allow for development above. The high ground water level, impacted by high tides and coupled with major rain events, regularly leads to flooding at the street level.
Once a week, the Public Services Department must activate the pumps using the smaller pumps for about two hours. In order to avoid odors from bacteria buildup and accumulation of contaminants, the water is pumped at least once per week. The City has other problem areas, mostly due to geography. When it rains in Coronado, there is flooding in a few predictable locations:
- First Street from B Avenue to beyond A Avenue
- Orange Avenue northbound and C Avenue from Fifth to Tenth streets
- Glorietta Boulevard, Pomona Avenue and Tenth Street (Five Points) intersection
- Alley between F and G avenues from Seventh Street to Tenth
- Fourth Street from Alameda Boulevard to G Avenue
- Country Club area, especially on Coronado Avenue from Acacia Way to Eight Street and on Eight from Balboa to Coronado avenues
- State Route 75’s southbound exit to the Coronado Cays
Flooding following rain in these locations is exacerbated when it occurs at the same time as high tides. Additionally, because these areas are quite spread out, it can be difficult to address flooding issues at the same time. Public Services offers sandbags, posts signs, erects barricades, installs traffic cones and otherwise helps with awareness and mitigation efforts.
The emergency response plan includes input from the city’s police, fire, public services and engineering departments. It provides information to guide and assist the City, through policies and procedures, to efficiently deal with all aspects of a flood emergency, such as would occur during an El Niño event.
According to weather forecasters, El Niño is a tropical weather pattern that occurs roughly once every three to seven years. It is characterized by the above-average warming of the surface temperature of the waters in the eastern portion of the Pacific Ocean that results in extreme weather, such as drought or flooding. Forecasters predict Southern California can expect to see a wet winter and marked increase in storms.
City staff is working to define all areas at risk of flooding; clear existing storm drains; drill public safety personnel in shore-based swift water rescue; monitor the channels that may bring potential flooding; identify trigger points that would require particular actions; ensure there are sufficient sandbags available to residents prior to significant rain events and remind residents that they are available at the normal locations: First Street and Alameda Boulevard, Fourth Street and Alameda and at North Beach; review and test the city’s alert and warning system; prepare information for the public on potential areas susceptible to flooding and personal emergency preparedness measures; and hire additional short-term maintenance personnel, as needed.
City staff has identified three projects to address flooding issues in the Country Club area, including corrections to the area’s storm line inflow and infiltration; Pine and North Beach outfalls rehabilitation; and Parker Pump Station generator and upgrades. None will be completed in time for this year’s potential El Niño. However, the projects, estimated to cost up to $2.8 million, are in various stages of planning, environmental review and design, and are expected to be completed over the next 3 to 4 years. Each will do much to address the enormous amount of tidal influenced, groundwater inundation in the Country Club area; provide more control to direct storm water; and reduce localized flooding.
Other flooding mitigation projects identified in the City’s Capital Improvements Program include upgrades to the Bandel Storm Pump Station Upgrades and storm drain improvements to Third, Fourth and Fifth streets and I Avenue at a cost of nearly $2 million.
Source: City of Coronado
