Letter and album: Flooding in Montara requires a solution from the county


Posted by on Sun, December 11, 2005

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County Department of Public Works delivering sandbags on Harte Street on November 29, the Tuesday after Thanksgiving. Click on any image to see the album.
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This is Harte Street, looking east from Cedar. This and the other photos in the album are from April 2005
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Cedar Street, looking north from Harte.

EDITOR’S NOTE: Flooding is a serious problem every year in some neighborhoods in Montara.  It is exacerbated by   the removal of trees, exposure of soil, increased hardscaping, and poor drainage.  These combine to increase the amount of runoff and the erosion it causes and reduce the number of places the water can drain or be absorbed.

I met Stephen Lowens, of Montarans United Against Flooding, at the Board of Supervisors hearing on the Local Coastal Program Update.  He came with photos of the flooding in Montara this November and last April, a letter to the supervisors, and proposal for solving the problem. We’re running a copy of his letter and an album of photos of flooding in Montara.  If you have more photos, especially as the rainy season wears on, send them to Coastsider, and we’ll add them to the album.  Click on any image to see the album.

This letter is intended to provide formal input and comment on the Midcoast Local Coastal Program (LCP) Update Project and the public meeting on December 6, 2005.

We have read the staff report prepared by Marcia Raines dated November 9, 2005, and we find that it has a gaping hole.  In the infrastructure section of the report, there are no policies related to flood control or to the stormwater collection system that is in place throughout unincorporated portions of the county.  That system is in significant disrepair and is failing on many counts due to the lack of formal policies in the design, maintenance, management, inspection and enforcement of stormwater collection.  The San Mateo County Department of Public Works has consistently refused to take action on this problem, and we surmise that the lack of official policy is a contributing factor to this lack of action.

Because of the lack of policy, homes are being flooded, soil is being eroded, and silt-laden runoff is entering our streams and the ocean many times a year during the rainy season.  This county has long ignored and buck-passed this issue, and the results are being felt by residents with no power to control the incoming waters.  Homes throughout the midcoast area are being flooded because of Board inaction; and the uncontrolled runoff from new development is the principal cause of this growing problem.  The only way this problem can be solved is for San Mateo County to take action on stormwater management on a comprehensive basis in the Midcoast area.

San Mateo County is far behind all other Bay Area counties in dealing with this issue.  Some counties have developed policies to allow urban development only in cities, where city standards apply.  Several counties have flood control districts.  Others have policies in their General Plan and/or a stormwater management plan.  San Mateo County is alone in avoiding the issue.

Click on "read more" to see the rest of this letter, including proposed policy letter from Montarans United Against Flooding.

 

As an example, here are excerpts from the Sonoma County General Plan - this is what San Mateo County should be doing:

"Existing Policy PS2-2g: Prepare a comprehensive analysis of the potential flood hazards and drainage impacts associated with adopted land use plans for each major watershed in the County. The County shall work with the incorporated cities to develop basin wide drainage studies and development fees for the purpose of identifying and mitigating the direct and cumulative impact of flooding which results from the loss of permeable surfaces. The County shall use proposed annexations, redevelopment agreements, revenue sharing agreements and the CEQA process as tools to ensure that incorporated development pays its fair share toward the studies and mitigation of downstream flooding impacts caused by upstream development.

"Pending completion of the above applicable drainage analyses, individual project applications shall be required to analyze and mitigate drainage impacts, based upon the land use plan, as determined by the Permit and Resource Management Department. If such analysis identified unmitigated and cumulative significant effects, including impact on downstream flooding, further environmental documentation may be required.

"In the event that the Permit and Resource Management Department determines that the project, when considered cumulatively with other projects to be undertaken in the drainage basin, will result in a significant effect with respect to downstream flooding, the project applicant will either: a) prepare a supplemental environmental impact report on such effect, or b) agree to modify the project to construct improvements or participate in a funding mechanism necessary to mitigate any downstream flooding impacts (such as posting a bond on funds prior to recordation of the final map in an amount to be determined by the Permit and Resource Management Department). Failure to modify the project or to propose further environmental documentation shall be grounds for finding the project inconsistent with the plan.

"Proposed Policy WR3-1l: Initiate a review of any sewer systems when they persistently fail to meet applicable standards. If necessary to assure that standards are met, the County may deny new development proposals or impose moratoria on building and other permits that would result in a substantial increase in demand and may impose strict monitoring requirements.4"

The "Stormwater Management Plan" adopted by the San Mateo City/County Association of Governments in November, 2003 is not a suitable replacement for the actions we are calling for.  When fully implemented, that plan will only govern development projects covering more than 10,000 square feet - a size that will not affect development on Midcoast parcels.  That plan also does not cover the issue of stormwater collection and flood control.

We note a particularly insidious aspect of San Mateo County policy, which is that development in the Midcoast is happening on a parcel-by-parcel piecemeal basis.  There has been no analysis of the cumulative impact of development as required by CEQA, and thus no serious attention given to the problem.  CEQA requires an EIR when a project of any size can be considered "cumulatively significant."  We believe the County may be in violation of CEQA requirements by NOT considering the cumulative impacts of Midcoast development.

We also note that the County’s Impact Mitigation Fee has not been increased since its inception in 1990.  If the County is serious about impact mitigation, it should update its mitigation fee ordinance with a new nexus study and adjust the fee annually on the basis of the local construction cost Index.  To do less is to doom the process to inadequate funding.

Attached to this letter is the picture worth 1,000 words.  It is a photo of a San Mateo County DPW crew making the annual delivery of sandbags to a residence in Montara.  This and a little maintenance of the ditches is all they are doing.  While we appreciate this help, it is a totally inadequate response to the problem, along with being tacit admission by DPW that the problem does exist.

MONTARANS UNITED AGAINST FLOODING has prepared a policy paper for the Board’s consideration that addresses this question in significant detail; a copy of that policy paper is attached to this letter.  We ask that the Board amend the County General Plan, the Montara-Moss Beach-El Granada Community Plan, and the LCP to include policies accepting stormwater management and flood control as a part of the community’s infrastructure.  We ask that the County develop a Stormwater Master Plan for the Midcoast, with elements of analysis, design, remediation of existing deficiencies, financing, regulation of retention of stormwater for new development on-site, monitoring of the system on an annual basis, and enforced penalties for violation of the requirements of the plan.  We ask that stormwater management be decoupled from street standards so that stormwater problems can be solved when roadway standards become an issue.  We take the position that San Mateo County residents deserve to be safe in their homes, and that safety extends beyond law enforcement to include safety from flooding.  We also believe that our precious coast cannot be well protected so long as unregulated runoff continues to flow into our streams and the ocean.

We look forward to your response.

Sincerely,

 


Stephen Lowens
Coordinator
Montarans United Against Flooding

Policy Paper

Proposal for Stormwater Management in the San Mateo County Midcoast Area

 

MONTARANS UNITED AGAINST FLOODING proposes that San Mateo County carry out the following steps to prepare the policy and action plans needed to regulate and remediate stormwater problems in the Midcoast area:

1. Stormwater management should be added to the Montara-Moss Beach-El Granada Community Plan as a part of the community infrastructure.  This element of the community plan will establish overall public policy in the area of stormwater management.  General statements of public policy to be included in this plan include the responsibility to develop a detailed Stormwater Master Plan,  the overall design standard for the system (i.e. 10 or 20 year flood level), the responsibility for construction and maintenance of the system (may be shared between the County and property owners as is the present case, but with better design controls), the means of financing the system, and a commitment to monitoring and enforcing the requirements of the plan.

A specific goal of the plan should be that all "public" stormwater (water from more than two properties) should be carried either in public rights-of-way or in easements granted to the public by landowners. The new plan should specifically decouple drainage management from roadway standards so that a "drainage only" project can be constructed if roadway standards become an interfering issue.  The plan should encourage combined construction of roadway and drainage where economically feasible, but should permit separate drainage projects where they are needed.

The General Plan and Community Plan should be amended to include policies similar to the following, taken from the Sonoma County General Plan:

"Policy PS-2g: Prepare a comprehensive analysis of the potential flood hazards and drainage impacts associated with adopted land use plans for each major watershed in the County. The County shall work with the incorporated cities to develop basin wide drainage studies and development fees for the purpose of identifying and mitigating the direct and cumulative impact of flooding which results from the loss of permeable surfaces. The County shall use proposed annexations, redevelopment agreements, revenue sharing agreements and the CEQA process as tools to ensure that incorporated development pays its fair share toward the studies and mitigation of downstream flooding impacts caused by upstream development.

"Pending completion of the above applicable drainage analyses, individual project applications shall be required to analyze and mitigate drainage impacts, based upon the land use plan, as determined by the Permit and Resource Management Department. If such analysis identified unmitigated and cumulative significant effects, including impact on downstream flooding, further environmental documentation may be required.

"In the event that the Permit and Resource Management Department determines that the project, when considered cumulatively with other projects to be undertaken in the drainage basin, will result in a significant effect with respect to downstream flooding, the project applicant will either: a) prepare a supplemental environmental impact report on such effect, or b) agree to modify the project to construct improvements or participate in a funding mechanism necessary to mitigate any downstream flooding impacts (such as posting a bond on funds prior to recordation of the final map in an amount to be determined by the Permit and Resource Management Department). Failure to modify the project or to propose further environmental documentation shall be grounds for finding the project inconsistent with the plan."

2. A stormwater master plan should be created for the Midcoast area, with the following elements:

A. Analysis: An engineering analysis should be made of stormwater runoff in the entire community, including upstream sources in undeveloped areas feeding the community, so that a proper design can be prepared.  The analysis should take into account the likely level of infill buildout of the community.  Areas that are currently subjected to flooding, or which might be subjected to flooding in the future, should be highlighted.  Besides identifying current and future problems, this analysis will allow the developers of future homes (or other structures) to know the anticipated flow rate at their property boundaries so that the County can inform them of the proper size of the driveway drain and require its construction to County specifications.

B. Design: A comprehensive stormwater management system should be designed for the community.  That system may retain or enhance the current system of ditches and driveway drains; however, it must be designed as a system.  The County, and not individual homehowners, must specify the size of the ditches and the driveway drains, so that downstream backups are not created by inadequately sized components.  The current County standard of a 12 inch pipe for a driveway drain is inadequate; the size must be related to the demand at each specific location.

The system should be designed to serve existing development AND likely infill for at least the next 20 years.  Where the ditch/driveway drain system is inadequate to prevent flooding in accordance with the 10- or 20- year standard, other methods of removing the water should be created.  For the problem areas, we foresee a combination of underground storm drains and retention ponds that return stormwater to bedrock as an economically feasible means of solving this problem.

C. Control at the Source for New Development: The County has created a policy that new developments must create plans to retain excess stormwater on-site.  The implementation of this policy is inadequate at the present time and must be enhanced.  At the present time, developers are required to submit a plan for stormwater retention after their plan has been reviewed by the Design Review Committee.  Such a policy makes it impossible for the public to have input on this key remediation, and leaves the actual retention measures out of public view.  Because the County has been so lax in creating and enforcing this policy, we believe it is important to have these conditions determined before Design Review is completed, so that the Design Review Board can see the project design in its entirety and can also act to review the appropriateness of the proposed retention methods.

San Mateo County needs to develop specific requirements for retention of on-site stormwater runoff.  The specific physical means to control the runoff needs to be part of the building permit application. Inspection of the construction of the controls needs to occur during the time that the building is being constructed.  Equally important, the controls need to be inspected on an annual basis to assure that they are maintained and performing their function.  Napa County has four inspectors on-staff whose job is to perform annual inspection of runoff controls.  Napa County also builds these controls into the property owners’ deeds, so that they become a permanent feature.  Only if San Mateo County creates a similar program can Montarans be assured that the promises of the development application are carried through into lifetime protection of our properties.

Montara’s terrain creates an additional problem that must be addressed by the stormwater retention planning.  It is not sufficient to simply compute the amount of impermeable coverage that will be added by a new development and then design a method to retain that amount.  Many Montara properties carry sheet-flow runoff from adjacent properties.  When that sheet-flow is concentrated during the process of development, additional burden is placed on downstream stormwater receptors.  The design of stormwater retention needs to include ALL sources of stormwater that are handled by a specific property.  The goal should be not to just stabilize the quantity of runoff, but also the time-gradient.

San Mateo County also needs to create better guidance for developers on how to manage stormwater runoff.  Contra Costa County has developed a "Stormwater C.3 Guidebook" for developers (cover page attached), aimed at responding to California Water Resources Board requirements, that can serve as a model for our County.

D. Remediation of Existing Deficiencies: In their letter of January 3, 2005, Karen Wilson and Chuck Kozak documented numerous examples of flooding in the Cedar/Date/Harte corridor in Montara.  We have no doubt that many if not all of these locations will be identified as deficient in the analysis step we have requested above.  The County needs to develop a plan and program to remediate these deficiencies.  Most critical is the flooding that is ongoing in the southern portion of the 1200 block of Cedar Street and the 800 block of Harte Street, where sandbags are most common.  If deemed appropriate by the analysis and preparation of the stormwater management plan, we support the proposal prepared by the Department of Public Works, May 17, 2001, to place culverts under Cedar and Harte Streets to carry the stormwater to a point further south on Montara Creek.  We ask that this culvert be engineered and sized to accept any possible impacts of future infill development in the drainage corridor.  We note an issue that the1300 block of Cedar Street is privately owned, and this may restrain the implementation of this culvert project.  We urge the County to use all means necessary, including eminent domain, to implement this project.  The privately owned street should be seen as a problem to be solved, not a roadblock to implementation.

Our own review of the Montara drainage system has identified numerous locations where driveway drains act as an impediment to stormwater flow, causing siltation and erosion.  In the 1200 block of Cedar Street, for example, the size of the driveway drains decreases as one proceeds downstream - exactly the opposite of what is required.  Once a design for the system has been established, the County should work with individual homeowners to resize existing driveway drains to the required standards.  In high priority locations, where a specific driveway drain is causing flooding or erosion of adjacent properties, the County should be granted authority to fix the problem expeditiously at County expense.

D1. High Priority Implementation Project: In their letter of January 3, 2005, Wilson and Kozak identified the location of Alta Vista and Drake Street as one that had been modified to the detriment of the Cedar/Harte/Date drainage area.  A modification to the roadway system at that location is sending water from Alta Vista into the Cedar/Harte/Date corridor.  We specifically ask that the Department of Public Works monitor that location during the coming rainy season.  If the DPW observations confirm the claims made in the January 3 letter, we ask that DPW add a drainage modification to that location IN ADVANCE OF FINAL PREPARATION OF THE STORMWATER MANAGEMENT PLAN.  We believe that this small project can have major beneficial impacts to the drainage corridor as a whole. E. Financing: Financing is perhaps THE key component to solving this problem.  We take the position that, had the County started to address this problem when the neighborhood first started voicing concerns many years ago, that remediation would have either been far less costly or not necessary at all.  Because the County has been SO slow to react to our concerns,  because ONLY the County can deal with this issue in a comprehensive manner, and because many Montarans have already spent considerable sums protecting their own properties from flooding caused by upstream development. we take the position that the County should bear the cost of remediating the existing deficiencies.  We note that the County currently has available approximately $1.6 million in fees collected as "mitigation fees" from new developments constructed in the Midcoast area in the last 15 years.  That fund should be the primary source of funding for remediating the deficiencies we have noted in this proposal.  If there are legal restrictions to using this money for purely stormwater purposes, we urge the County to use its counsel to determine the legal steps needed to free up the money to be used for this purpose.

Also, the Impact Mitigation fee has not been increased since its inception in 1990.  It has thus failed to keep up with the increasing cost of construction.  The impact fee ordinance should be revised to adjust the fee proportional to the local construction cost index.

F. Monitoring and Enforcement: We anticipate that the ultimate stormwater management plan for Montara will not consist of a community-wide culvert system, but will rather be similar to the ditch/driveway drain system that we have today, enhanced by some culverts and by retention ponds in private and possibly public areas.  Such a combination of public/private responsibility cannot rest solely on the good intentions of the participants.  We have already seen examples in the community where retention measures were included in development plans but not implemented.  To be successful, to assure that downstream properties are indeed protected, a program of monitoring and enforcement needs to be created.  Construction sites should be inspected regularly to assure that stormwater retention requirements are being met.  An occupancy permit for the new home should not be issued until the inspector certifies that all conditions of the building permit have been satisfied. All stormwater retention facilities created under this plan should be inspected on an annual basis.  Penalties should be established for non-compliance, and the DPW should be granted the power to perform maintenance on non-compliant properties if all else fails.  Without this vital step, the overall goals of this program will not be met, and we will be back before you in future years asking for your help once again.