400 Series - Mapping and Regulations

400 Series- Mapping and Regulation

San Anselmo is very strong in its mapping sophistication thanks to its partnerships in Ross Valley and Marin County. The first Flood Insurance Rate Maps (FIRMs) for the area were developed in the 1970s, revised in the ‘90s, and again in 2014. The most recent flood map was started by a FEMA consultant and peer-reviewed by our local consultant, Stetson Engineers, based upon local High Water Mark initiatives. Our 2005 flood was close to the 100-year event and formed the basis of the modeling which informed our Capital Improvement Plan.

Activity 410 – Floodplain Mapping

(802 pts)
• 412 (a) Contributing to a New Study (290 pts)
San Anselmo participated in the revision of the 2009 FIRM in two key ways.
First, community members and staff collected and supplied high water marks from the 2005 flood event, which were used to develop Base Flood Elevations (BFEs). Second, the hydrologic model developed by Stetson Engineers with funding from our flood control district was also incorporated. Both of these are documented in the Flood Insurance Study meeting minutes attached here.
Attachment: 412a FIS Study Meeting Minutes

• 412(b) Funds contributed to new maps
• 412(c) Flood studies reviewed by state (60 pts)
• 412(d) Higher study standards (160 pts)
• 412(e) More restricted floodway (110 pts)
• 412(f) map flood related hazards (50 pts)
• 412(g) cooperating technical partner (132 pts)
No credit requested

Activity 420 – Open Space Preservation

(2020 pts)

• 422(a) Keeping land vacant (1450 pts)
San Anselmo is built-out along the creek. It developed very quickly after 1900 from a summer camp along the creek and traditionally focused development here. The Town does maintain Creek Park as open space along the flood zone in downtown, however due to its small size we are not applying for credit for this activity.

As written in the Resolution 1492 adopting the Conservation and Open Space Plan, “the [Town] further declares its intention of adopting the accompanying amendment of the general zoning regulations in order to preserve a minimum 70-foot channel between buildings for the discharge of flood water along San Anselmo creek and its tributaries, and to create thereby, a Creekside greenway for preserving vegetation and other uses.
Attachment: Resolution 1492 Adopting Open Space Plan

The Town also has a Floor-Area-Ratio (FAR) ordinance that prevents development of over 35-45% of parcel areas.
Attachment: Resolution Adopting FAR

• 422(b) Deed Restrictions (50 pts) Ensuring no future development.
no credit requested

• 422(c) Natural Functions open space (350 pts)
On July 23, 2015 San Anselmo Town Council approved the an ordinance revising the Town stormwater quality protections and regulating the creation of impervious surfaces on private property. Infiltration of rain and stormwater runoff into the soil is a critical natural function. Residents must now seek pervious alternatives or install bioretention for every project creating over 150 square feet of impervious surface.
Link: Staff Report for second reading of revised stormwater ordinance

• 422(d) Special Flood Hazard Open Space (50 pts)
no credit requested

• 422(e) Open Space Incentives (250 pts)
San Anselmo enforces a 15-foot construction setback from the top of creek banks.
Length of creeks=20,200 feet x ~50 feet wide =1,010,000 square feet =23.1 acres

San Anselmo Municipal Code Title 7, Chapter 12.

• 422(f) Low Density Zoning (600 pts) 5 acre lot minimum
no credit requested, however see 422 a

• 422(g) Natural Shoreline Protection (120 pts)
San Anselmo contributes to the regulation by state and federal agencies to protect natural shorelines. Through the Marin County ‘Permit Coordination Meetings’ we work with riparian landowners to implement biotechnical bank stabilization projects. If a creek bank needs to be rebuilt we refer, and often accompany, the owner to these meetings. Maybe these are uniform credits, but we go above and beyond state laws.
Link: Marin Project Coordination Meetings

Activity 430 – Higher Regulatory Standards

(2,042 pts)

The Town has adopted the 2013 California Building Code:
Link: Town Municipal Code Title 9, Chapter 1

The Town Municipal Code governing flood protection is linked here:
Attachment: Title 7, Public Works, Chapter 11 Protection of Flood Hazard Areas, Chapter 12 Watercourses

• 432(a) Development Limitations (1330 pts)
Prohibiting fill in floodplain beyond what is required in floodway.
No credit requested

• 432(b) Freeboard (500 pts)
Per the CBC, San Anselmo requires 1’ Freeboard and requires that utilities and ductwork are elevated or floodproofed. aFRB=aSFHA

• 432(c) Foundation ‘Engineered’ (80 pts)
No points requested (we require design professional if cripple wall >14”)

• 432(d) Cumulative Substantial Improvements (90 pts)
No Credit Requested

• 432(e) If substantial improvement <50% (20 pts)
No Credit Requested

• 432(f) Protection of Critical Facilities (80 pts)
CBC says that ‘essential facilities’ must be designed to higher standards.

• 432(g) Enclosure Limits (240 pts)
The Town building department requires residential living space be elevated above the BFE. Area below the BFE must be unfinished and vented.

• 432(h) Adopting International Building Code (100 pts)
Yes. San Anselmo has adopted the 2013 California Building Code, including Appendix G: Flood Resistant Construction, 2013 California Residential Building, Electrical, Mechanical, Plumbing, Energy, and Historic Building Codes. Also the 2010 Green Building Standards Code and the 2012 International Property Maintenance Code
Link: Town Municipal Code Title 9, Chapter 1

• 432(i) Local Drainage Protection (120 pts) building code specifies local drainage
Yes, according to the Chapter 18 of the California Building Code, local drainage considerations are required. No attachment.

• 432(j) No elevation exemption for manufactured homes (15 pts)
No points requested; no manufactured home parks.

• 432(k) Enforcement of Coastal A Zones
No points requested.

• 432(l) Special Flood Related Hazard Regulations (100 pts)
No points requested.

• 432(m) Other Higher Standards (100 pts)
San Anselmo has consistently adopted resolutions confirming the need to modify the state construction codes because of local conditions. San Anselmo grew out of the great earthquake and fire that devastated San Francisco in 1906, thus has been protective against these types of dual-catastrophes. Every time a resolution of this sort is passed, it is accompanied by a report on the Town’s climatic, geographic, and topographic profile, which mentions floods and landslides. Specifically, the Town requires buried utilities, bans non-metallic cable, requires higher garage ceilings, larger door sizes, and non-combustible roofs.
Attachment: Resolutions 4051 Re: modifications to state construction/building codes because of local conditions.

• 432(n) Regulatory Mandate Required by State (20 pts)

• 432(o) FEMA staff training (67 pts) Two Public Works Staff took a FEMA NFIP Agent Training Workshop on February 19, 2014 in San Rafael
Attachment: email and certification that we attended the training.

Activity 440 – Flood Data Maintenance

(222 points)

• 442a. Additional Map Data (160 pts)
San Anselmo participates in MarinMap, which is a consortium of public agencies cooperatively maintaining a Geographic Information System (GIS) for public use. Data for MarinMaps comes directly from the Assesor’s Parcel information and is kept current by paid staff.
Link: About MarinMap

MarinMap’s public data viewers include a FEMA Flood Map and Map Change
Link: MarinMAp Flood Map Viewer
Marinmap also has a general map viewer which contains layers of other hazards such as Dam Inundation zones, geologic faults, and liquefaction potential.
Link: MarinMap Hazard Viewer

Credit requested for this activity includes:
o AMD1 =20 points, for showing the SFHA boundaries, corporate limits, streets, and parcel or lot boundaries
o AMD2 = 26 points, for a GIS layer that shows buildings, building outlines, or building footprints, and the building information is kept up to date to reflect new construction
o AMD3 = 12 points, for showing floodways or coastal high hazard areas
o AMD4 = 12 points, for showing base flood elevations
o AMD5 = 10 points, for including FIRM zone attributes (e.g., A3, VE, etc.)
o AMD6 = 10 points, for showing the 500-year floodplain elevations or boundaries
o AMD7 = 12 points, for showing areas of the community subject to other natural hazards, such as landslides, subsidence, stream migration, and soils unsuitable for septic fields
o AMD8b = 8 points, if the community’s GIS includes topographic contour lines,
o AMD10 = 6 points, for including overlays or layers for all FIRMs in effect after the date of the community’s application to the Community Rating System (CRS)
o AMD12 = 14 points, for areas with natural floodplain functions (e.g., wetlands, designated riparian habitat, flood water storage areas)
Attachment: MarinMap screenshots

• 442.b. FIRM maintenance
San Anselmo maintains copies of all FIRMs and studies going back to 1977, when the maps were first issued here. Copies of map covers are included here.

• 442.c. Benchmark Maintenance
San Anselmo has an old list of benchmarks, approximately four of which are still there and within one mile of a SFHA. None of these benchmarks are in the CORS database.

Activity 450 – Stormwater Management

San Anselmo complies with the California General Permit and NPDES for stormwater discharges, and is proactive about stormwater management regulation and enforcement. The Town is a part of the Marin County Stormwater Pollution Prevention Program (MCSTOPPP), which provides assistance, training, educational materials, and much more.
Link: MCSTOPPP website
As of 2014-2015, the California Water Quality Control Board requires San Anselmo to comply with its new Phase II Stormwater Permit for MS4s. Accordingly, we are in the process of refining many aspects of this activity including ‘post-construction’ requirements (aka Low Impact Development (LID) and design), construction site erosion and sediment control, creek TMDL water quality monitoring, education, and the corresponding chapter of the Town municipal code.

452.a. Stormwater Management Regulations
(1) Size of development. San Anselmo, and all the communities in MCSTOPPP, is using a new Guidance Manual (BASMAA Post-Construction Manual; Design Guidance for Stormwater Treatment and Control for Projects in Marin, Sonoma, Napa, and Solano Counties) that regulates the creation of additional impervious surfaces down to 2,500 square feet for single family homes, and 5,000 square feet for other small projects. On July 23, 2015 San Anselmo Town Council approved the an ordinance revising the Town stormwater quality protections and regulating the creation of impervious surfaces on private property down to 150 square feet.
Link: Staff Report for second reading of revised stormwater ordinance
Attachment: San Anselmo LID design guidance
Link: Marin County LID Design Guidance

(2) The Design Storm for these systems is the 10-year storm. The memo included here is a model simulation using local rainfall data to verify that the bioretention standards used in the Guidance Manual controls runoff from the 10-year storm.
Link: Bioretention design controls 10-year storm
In the creek channel itself, San Anselmo is pursuing a flood control program designed to keep the 100-year storm within the banks.

(3) Both San Anselmo and Marin County have 'Low Impact Development' requirements and design guidance for new construction projects.
See attachment 452a1
Link: Marin Development Projects Page

Additionally, San Anselmo is adopting LID practices in its own Capital Improvement Projects. Last year the Town was awarded a $500,000 grant for implementing three LID projects on Town property and the project has moved to the design phase.
Link: Town Council staff report for LID Demonstration Project

(4) Public inspections & maintenance.
Section 5 of the Marin County Guidance Manual lays out steps to complete an Operation and Maintenance Plan for each stormwater control system. Annual inspections and repairs are required, but the responsibility of the property owner.

Attachments: Resolution 3633, Intention to Comply with California General Permit for stormwater discharges

452 (b) Watershed Master Plan (315 pts)
The closest thing San Anselmo has to a Watershed Master Plan is the Capital Improvement Plan developed by the flood control district. Because this does not address the regulatory standards for new development, it does not qualify for CRS credit.

452 (c) Erosion and Sediment Control Regulations (40 pts)
San Anselmo complies with the State requirements for erosion and sediment control regulation using the procedures developed by Marin County and MCSTOPPP. The following Erosion & Sediment Control Plan submittals are required for every grading permit issued, which is required for any cut or fill above 25 cubic yards.
Link: Erosion and Sediment Control Plan Application
Erosion and Sediment Control Plan Review Procedures

452 (d) Water Quality Regulations (20 pts)
The BMP’s required by the Guidance Manual described in 452(a) are designed to improve water quality. Projects that develop an acre or more are required to install bioretention, which is a permanent structure designed to infiltrate and improve the quality of stormwater runoff.