Watershed description. The Topanga Creek watershed is the second largest watershed in the Santa Monica Mountains. The watershed is a north-south trending, Yshaped canyon, that covers approximately 18 square miles with elevations reaching from over 1700 feet to sea level. The 9-mile axis of the main drainage drops an average of 250+feet/mile, creating narrow, steep sided canyons with exposed walls of sedimentary rocks dating from 14-17 million years ago.
Topanga Creek is a geologically young, intermittent stream with perennial pools that is fed by numerous tributaries along its two main branches. The mouth of the creek emerges into Santa Monica Bay through a small estuary, which has created a major surfing beach at Topanga Beach. Topanga Creek is an important and relatively natural creek in the Santa Monica Mountains, which supports a large diversity of plants and animals, many of which are increasingly rare.
Since the early 1900's, a predominantly rural community has developed to the present population of approximately 11, 000 residents. The community initially developed along the creeks, Old Topanga Canyon Road, and Topanga Canyon Boulevard (State Highway 27), and has more recently expanded into the surrounding hills and ridges. Highway 27 itself has evolved into a major commuter route from the San Fernando Valley to the Westside and the beaches. Thousands of people visit the canyon to enjoy the numerous parks of the Santa Monica Mountains National Recreation Area that are located here.
1.0 quantifying the flood hazard risk
1.1 FLOODPLAIN MANAGEMENT
1.1.1 COMPARISON OF APPROACHES
There is general agreement that a flood hazard does exist in Topanga Canyon, although there are differences of opinion about the exact nature and the degree of hazard. A comparison of hazard management approaches by Los Angeles County Department of Public Works (DPW) and the Topanga Canyon Floodplain Management Citizens Advisory Committee (TAC), appointed by the Board of Supervisors, may provide a clearer understanding of the differences between the two approaches.
DPW approach. The Floodway Ordinance proposed by DPW would regulate properties along Topanga Creek and prohibit any measures that would disturb the channel and raise water levels. Although the prime intent of the approach is to prevent any increase in flood hazard to properties located in the floodway, the practical result is to actually increase the hazard to those properties, by legally prohibiting them from constructing flood protection devices. Furthermore, the floodway puts the entire burden of dealing with the flood hazard on the property owners along the creek, irrespective of the amount of increased runoff created from other areas of the watershed. The consequences to the property owners are detailed further elsewhere in this report. DPW attempts to deal with the end result of the flood hazard situation without correcting the underlying causes.
TAC approach. The prime intent of the approach by TAC is to reduce the flood hazard and protect existing life and property. To accomplish this, TAC proposes to develop and implement a watershed management plan which would reduce peak flow runoff, erosion, sedimentation, and flood hazard while protecting the riparian habitat, infrastructure, and existing development. This plan would require the cooperation of the residents, property owners, and government agencies over the entire watershed instead of just the residents and businesses in the narrow band along the Creek itself. This preventive approach is intended to benefit all residents, property owners and visitors in Topanga Canyon, including the public agencies which own facilities such as roads, bridges, and utilities.
An analogy. Solving the flood hazard problem is analogous to solving the problem of dealing with emissions of pollutants from industrial facilities. The approach by DPW is an ìend of pipeî solution, in which the pollutants are trapped and neutralized by equipment using a process which is an afterthought to the industrial production itself. The approach by TAC is a ìpoint source reductionî solution, analogous to a modification within the industrial process itself, in which the production of pollutants is itself reduced. A number of industries have found that modifying their production technology was not only more effective than the ìend of pipeî solutions, but more economical as well.
1.1.2 County designated floodways
Several years ago the Los Angles County Department of Public Works (DPW) proposed to the Board of Supervisors that a Floodway Ordinance be implemented in upper Topanga Canyon with the primary objective of prohibiting development in areas having significant flood hazards (Section 3.4). A careful review of DPWís Floodplain Management Program revealed that a County Designated Floodway did not offer:
Adequate protection for existing life and property.
Reduction in peak flow runoff, or protection from increases in peak flow runoff.
Increase in protection for the infrastructure of the State and County, and consequently no potential reduction in flood damage repair claims.
Reduction in business losses from road closures.
A proportionate burden for the existing creekside homeowner (i.e., in terms of loss in property values, uninsured losses, and prohibitive regulations to rebuilding in the event of a non-flood related loss from fire or earthquake, the creekside homeowner bears most of the burden of the floodway).
Protection for the riparian habitat.
What the Floodway Ordinance fails to provide, and what our community needs, is flood hazard protection for residents and their property, for infrastructure (i.e., the roads and utilities of which the County is the biggest owner), and preservation of the riparian habitat.
1.1.3 Other approaches to floodplain management
Other floodplain management plans typically have a broader approach than that proposed in the Floodway Ordinance. For example, the California Department of Water Resources model Floodplain Management Ordinance [18] includes the following general objectives:
Protect human life and health
Minimize expenditure of public money for costly flood control projects
Minimize the need for rescue and relief efforts
Minimize prolonged business interruptions
Minimize damage to public facilities and utilities such as water mains, roads, and bridges located in areas of special flood hazard
Maintain a stable tax base to minimize future blighted areas caused by flood damage
Ensure that property owners in areas of special flood hazard assume responsibility for their actions and that potential buyers are made aware that a property is in an area of special flood hazard.
This expanded set of goals encourages a broader range of solutions to flood hazard problems in comparison to the single tool strategy proposed in the Floodway Ordinance and is economically superior in the long run.
1.2 WHATíS AT RISK
As demonstrated by the 1980 flood, the worst recorded for Topanga Canyon, the risks of flooding primarily impact the:
Millions of dollars worth of roads, bridges, and utilities, including a main commuter route through the Santa Monica Mountains (Highway 27).
Public safety while traveling on roads and bridges.
Access to hundreds of homes.
Creekside businesses and residences.
Preservation of the riparian habitat and environment.
The predominant risk from flooding is from erosion and undermining of roads adjacent to Topanga Creek and its major tributaries. Over the last 20 years significant damage has occurred to Old Topanga Canyon Road, Topanga Canyon Boulevard, and the access roads to some residences. The risk to those who travel the roads under storm conditions, especially travelers unfamiliar with these conditions, is substantial. In addition, repeated emergency repairs of the infrastructure wastes tax dollars on identified risks. Major damage associated with actual flooding of business and residential structures is rare and is largely covered by the self-sustaining National Flood Insurance Program (NFIP) run by the Federal Emergency Management Agency (FEMA). Historically, a structure in Topanga is more threatened by the effects of unstable saturated soil, than from the risk of flood damage, which is typically cosmetic (e.g., water damage to wall board and contents).
A major concern with existing policy is that it allows increased peak flow upstream which poses a threat to downstream structures that have not been at risk in the past. Since the County owns many of these facilities, it would appear to be in their best interest to decrease potential flood hazards at the source. A pro-active approach could prevent damage to roads, utilities, bridges, culverts, and the riparian habitat by decreasing the potential for flooding.
The Topanga Creek Watershed Management Plan proposed by TAC will cost-effectively address these issues and provide a realistic means to mitigate the flood hazard. This alternative approach can work in Topanga because the watershed is small and is still in a relatively natural condition. Our community is organized, and has sufficient knowledge to create and carry out such a plan.
Findings:
The solution to flood hazard mitigation in Topanga is not another County Designated Floodway because:
Existing life and property are not protected.
Existing roads and the utilities are not protected from the present flood hazard.
The riparian habitat is not protected (i.e., the creek channel and riparian habitat is destroyed by uncontrolled increases in surface runoff).
Channelization of the creek is unacceptable to the community.
The Floodway has no community support.
1.3 QUANTIFYING THE RISK
The standard engineering practice for quantifying the risk of flooding requires that a design storm be selected, that a hydrologic model be used to calculate the peak flow runoff generated by the design storm, and that a hydraulic model be used to calculate the maximum height of water at a particular location. Thus, three separate processes are involved, all of which involve highly subjective judgments. Details about the modeling process used by the County are given in Appendix M.
A 50-year storm has been designated by the County as an appropriate storm for assessing flood hazard in Topanga Canyon. The term 50-year storm means that a rainstorm of this intensity will occur on average only once in 50 years.
2.0 PRESENT PRACTICES EXACERBATING THE FLOOD
HAZARD
Present practices that exacerbate the flood hazard include those associated with grading, paving, brushing, the use of inappropriate or poorly compacted or placed fills, floodplain infilling, and lack of runoff mitigation measures for new construction.
2.1 runoff from new developments
To determine the impacts of the existing County policy, several recent developments in Topanga were reviewed. Three case studies are given. A description of the hydrologic model used to predict the runoff in these cases is given in Appendix M.
Case 1: Summit Pointe. This tract consists of about 79 acres and 83 home sites on an extensively graded site near the summit of Topanga Canyon Boulevard. (see Figure A1). To evaluate the impact of the development on peak flow runoff, the amount of runoff from the pre-developed or natural condition was compared to the developed condition. For the undeveloped state, the amount of runoff (peak flow Q) was calculated based on a 50-year storm, with a burned watershed and maximum soil saturation. Thus, to evaluate the undeveloped condition, ìworst caseî inputs to the hydrologic model were postulated to compute a peak runoff Q=186 cfs. In contrast, the Q calculated for the developed condition was 188 cfs. Therefore, the conclusion of the hydrologic analysis presented to, and accepted by, the County was that the runoff from the project site was the same in both its undeveloped and developed states. A more detailed review of this project is given in+[1].
Looking at the views depicted in Figure A-1, which show the extensive grading and paving and the use of concrete swales, it is impossible to accept that the peak flow runoff from the current developed situation is no greater, and presents no greater flood hazard than, from the same area prior to development. A procedure or theory which reaches this conclusion needs to be changed; and as a result of the study in [1], some changes were made by the County, as described in Case 2.
Case 2: Canyon Oaks. This proposed development was located approximately a half mile east of Summit Pointe on about 260 acres. A mixed land use of homes and golf course was proposed with several million yards of earthwork. The manner used to evaluate the runoff from this development was significantly different from that used in Case 1 because the Case 1 study reported in [1] led the County to adopt a new standard for determining pre-development runoff. DPW was instructed by the Board of Supervisors to implement a policy for upper Topanga Canyon that prohibited any increase in stormwater runoff from new tract development. This change in policy was interpreted by DPW to mean that no increase in peak clear flow would be allowed for the developed relative to the undeveloped condition. Peak flow comparisons between the developed and undeveloped conditions were performed for the 10, 25, and 50 year storms [12], which indicated that the development could meet the ìno increase in peak flow runoffî standard.
Case 3: 2 parcel lot split. About a half mile south of Canyon Oaks extensive grading was performed on an approximately 3 acre site to construct 2 building pads (see Figure A-2). Although the natural condition of the site relative to runoff was completely changed, no mitigation was required to limit the amount of additional runoff generated at this site. In addition to runoff, significant erosion also occurred. The first year after grading enough erosion occurred to fill one of the basins shown in Figure A-3, which is off-site about 100 yards downstream. This example is typical of the problems caused by extensive grading on the runoff characteristics of a site and the amount of sediment it generates. It also illustrates the need for additional oversight by the County to insure that the accumulated impact of such sites on the amount of runoff and sedimentation is not allowed to continue to increase the flood hazard in Topanga.
Findings:
Current policies do not deal with runoff in a comprehensive, consistent manner.
By using only a ìworst caseî scenario for the pre-development condition (e.g., saturated soil, burnt watershed), the actual ability of the site to retain storm runoff is substantially underestimated in most circumstances. Such scenarios make the amount of runoff generated by a developed site (e.g., as shown in Figure A-1) appear more similar to that generated by an undeveloped site than is true except in rare and extreme circumstances.
The Board of Supervisors directive of February 11, 1993 that prohibits increase in stormwater runoff from new tract development has been limited by DPW to peak flow and worst case soil conditions. A more representative approach is warranted where various rainfall intensities and levels of soil saturation and permeability are used so more realistic comparisons may be made.
In cases where lots are graded but are not built, the sedimentation and erosion problems have not been dealt with effectively. A comprehensive, watershed-wide policy that addresses preventing increased runoff under a range of conditions would help resolve these difficulties.
Recommendations:
A2.1-1 Establish a policy that limits stormwater runoff and sedimentation from new development to that which occurs over naturally existing terrain under all conditions.
A2.1-2 Establish a policy of using a broader spectrum of soil conditions to perform runoff comparisons between the developed and undeveloped site.
2.2 infrastructure maintenance/improvement practices
Infrastructure maintenance and construction activities (e.g., road and shoulder work, culvert construction, line clearance) within the watershed have had a major effect on the ability of the surrounding environment to absorb water, recharge groundwater reserves, stabilize embankments, and hold sediments.
2.2.1 Shoulder fill and dumping
A common practice along Topanga roadways is the use of fill on the road shoulder that generates excessive amounts of sedimentation and deeply cut erosion paths (Figure A-4). Also dumping soil (Figure A-5), from road clearing elsewhere along the roadside, is a standard maintenance practice for rebuilding eroded slopes. This increases sedimentation and runoff as well as degrading the natural slope stability provided by the vegetation, which is damaged or covered over by the dumped soil.
Findings:
The use of loose fill materials and dumping along road embankments leads to excessive sedimentation.
Dumping soil down embankments destroys trees and plants that might otherwise stabilize the embankment.
Recommendations:
A2.2.1-1 Use shoulder fill that can not be easily eroded away.
A2.2.1-2 Cease dumping loose soil over embankments.
2.2.2 Trees
Current practices which impact tree health include inappropriate pruning and topping; storing soil, placing fill and paving over root structures; and indirect injury to trunks and branches by machinery or cars. There are well known industry standards which directly prohibit topping during line clearance and outline specific practices which can preserve tree health during construction. The threatened trees and riparian vegetation serve a critical role in maintaining streambank integrity, allow for ground water recharge, help dissipate and reduce flow velocity and create an invaluable biological resource. The Significant Oak Woodland of the Topanga Watershed is specifically protected by the Malibu Land Use Plan and the Los Angeles County Oak Tree Ordinance. Damaged trees significantly increase the flood hazard, increase maintenance costs by encouraging stream bank instability, and place at risk an irreplaceable resource.
A January, 1996, study of Los Angeles County construction and culvert maintenance practices along a portion of Old Topanga Canyon Road (Appendix E) revealed numerous instances where trees in the riparian zone were being severely impacted (Figure 9). The estimated value of the 135 trees in that 3.5 mile stretch is over $2.4 million. Using this
Figure A-1. Summit Pointe development.
Figure A-2. Grading practices which increase sedimentation and peak flow runoff.
Figure A-3. Potential locations for detention basins, existing sites.
value as a basis for estimation, the over 2,000 trees in the riparian zone along Topanga Canyon Blvd. would be worth at least $35 million. These values are derived using the International Society of Arboriculture Standard Formula Method and are actually quite low, as they do not reflect the cost of reinforcing and stabilizing stream banks that fail after the trees die and can no longer serve that function.
Findings:
Current road maintenance practices are harmful to stream and roadside trees and vegetation.
Recommendations:
A2.2.2-1 Preserve and enhance the function of the existing riparian vegetation.
2.3 Grading and brushing
The recent practice of clear cutting the brush around a new development (Figure A7) increases both erosion and runoff while not significantly reducing the fire hazard over methods that retain a more natural condition, which retains more runoff and sediment.
Grading for a development may generate additional runoff by reducing the absorption of water into the soil and by conducting the runoff away from the site through the use of swales and drains (Figures A-1, A-2, and A-8).
Findings:
Grading and brushing practices can increase peak flow runoff.
Recommendations:
A2.3-1 Establish practices which make reduction of peak flow runoff an important element in the selection of a grading and brushing procedure.
A2.3-2 Minimize the removal of existing mature vegetation.
Figure A-4. Erosion of road shoulder fill.
Figure A-5. Soil dumping along road embankments.
Figure A-6. Tree impacts from road maintenance practices.
2.4 Alteration of stream flow characteristics
There are many examples where individual property owners or government agencies have filled in parts of the floodplain or constructed structures, such as bridges or buildings, which increase the downstream flood hazard. There is also the issue of altering the stream flow to reduce the flood hazard at a particular site. This is illustrated by the berm, shown in Figure A-9, that was constructed to protect some of the property, owned by the SMM Conservancy in Red Rock Canyon, from flooding as a result of the 1993 fire in this watershed. The berm is intended to confine the potential increased flow in the main part of the watercourse. The consequence of this, however, is to increase the peak flow downstream because the natural impounding of water by the floodplain is prevented, and to increase erosion in the channel due to heightened velocities. It also endangers trees lining the stream because of undermining, as well as burial, of their roots, and because their trunks are covered with the berm. This example highlights the need for a balanced approach where the need for flood hazard reduction is weighed against the consequences to the environment and the potential increase of erosion and flooding, especially for the downstream properties.
Recommendations:
A2.4.-1 Provide identification and protection of sites particularly vulnerable to erosion or obstruction in the Watershed Management Plan.
A2.4-2 Require that projects which alter the stream flow characteristics document their impact on downstream properties and mitigate any significant increases in flood hazard and environmental degradation.
Figure A-7. Results of clear cutting and disking for fire protection and lot development.
Figure A-8. Examples of grading and infill practices which generate increased peak flow runoff.
Figure A-9. Example of an alteration of the stream flow characteristics. Here a berm was
placed adjacent to the creek to prevent flooding of nearby facilities.
Figure A-10. Large pieces of debris that should be removed from major watercourses.
2.5 debris hazard
Illegal dumping that clogs culverts and small bridges is a major hazard. Occasionally large pieces of natural debris (typically trees) are washed into a major watercourse, as illustrated by the two trees depicted in Figure A-10, which are in the middle of the creek near 600 Old Topanga Canyon Road. Debris of this size is a major flood hazard because it tends to get jammed under bridges or in culverts, or gets caught in trees adjacent to the creek.
Recommendations:
A2.5-1 An annual monitoring program that identifies dumping sites prior to the rainy season and ensures debris removal is needed. Also a program for removal of large pieces of natural debris is needed.
2.6 Emergency road maintenance practices
Over the last 20 years, most slope stability projects for the roadways in Topanga have been done as emergency flood repair activities. This has lead to uncontrolled channelization of several sections of the main watercourses without adherence to established planning practices, reviews, or public comment. Many of these projects are poorly engineered and require extensive maintenance (Figure A-11).
Findings:
Emergency slope repairs have not performed well and require extensive maintenance.
Recommendations:
A.2.6-1 New designs and approaches are needed that preserve the natural setting of the watercourses while providing slope stability.
Figure A-11. Results of emergency repairs at various locations along Topanga Canyon Boulevard and Old Topanga Canyon Road.
3.0 REVIEW OF PRESENT FLOOD HAZARD MITIGATION POLICY AND REGULATIONS IN TOPANGA CANYON
Regulation is a primary tool of floodplain management. The appropriateness of the proposed regulation has been the center of controversy in the Topanga Canyon community over the past six years. Baseline regulations have been promulgated by FEMA/NFIP (i.e., Federal Emergency Management Agency, National Flood Insurance Program). The Department of Public Works (DPW) has proposed the use of more restrictive regulations. The governing regulations are outlined in this section and their impact is discussed.
3.1 federal programs: FEMA/NFIP/crs
3.1.1 NFIP Regulations.
The National Flood Insurance Program (NFIP) has a statutory single objective: protection of life and property from flooding. Government disaster assistance costs have been successfully transferred to the private sector beneficiaries of floodplain locations, in exchange for mitigation of flood risk by floodplain management. The Program provides valuable coverage for those at risk at no cost to the government (i.e., it is self-insured). Flood insurance premiums are based on flood risk as measured by the elevation of the lowest floor of a structure compared to the elevation of the 100-year base flood.
The availability of the NFIP insurance is based on an agreement between local communities and the Federal government. Communities must implement floodplain management measures to reduce future flood risks to new or substantially improved structures in flood hazard areas. In exchange, the Federal government will make flood insurance available within the community as a financial protection against flood losses that do occur. Participation also ensures that the local government will be eligible for Presidentially-declared disaster relief funds to repair roads and bridges. The County entered the NFIP Regular Program in 1980 which qualified local property owners for full flood insurance coverage at actuarial rates that vary according to location.
3.1.2 crs program
The Community Rating Service (CRS) program is an experimental (1990) incentive plan, coordinated at federal, state and local levels. It offers "points", which lower insurance premiums to local governments, for various activities such as Citizens' Advisory Groups, Public Information Activities, Early Warning Systems, Master Stormwater Design Plans, Flood Hazard Mitigation Plans, and Mapping and Higher Regulatory Standards. It also qualifies the County for state and federal mitigation funds. A Repetitive Loss Plan, designed to eliminate repeatedly damaged and unsafe structures, is a requirement for participation in the CRS Program. The CRS program encourages the development of alternative programs to reduce flood hazards, recognizing that creative solutions may better fit the needs of a special locale; that is, the CRS "require(s) that the community contact other agencies for solutions and look at a variety of possible ways to prevent and reduce flood losses." The goal of this voluntary program is to encourage floodplain management programs to go beyond the minimum standards specified in the NFIP regulations.
Findings:
The proposed Topanga Creek Watershed Management Plan would be able to gain the County significant "points". See CRS Repetitive Loss Plan in Appendix K.
Recommendations:
A3.1.2-1 Require DPW to do a comparative analysis of CRS credit points for the proposed Topanga Creek Watershed Management Plan and the Proposed Topanga Floodway Ordinance.
3.1.3 mitigation of unsafe conditions
The present federal regulations relevant for Topanga Canyon include the Flood Insurance Rate Maps (FIRM), which delineate flood boundaries and water elevations of the Special Flood Hazard Area (i.e., the area inundated by the l00-year storm), and the risk premium zones into which the community has been divided. Title 44 Code of Federal Regulation Chapter 1, 60.3 (Appendix D, pp. 2-13) details floodplain management criteria for flood prone areas. The existing requirement is for the lowest floor of a new structure to be elevated to or above the 100 year base flood elevation. Section 59.1 of Chapter 1 requires substantially damaged existing structures to be elevated to or above the 100 year storm. Damage of any origin equaling or exceeding 50% of the fair market value (before the damage occurred) triggers this clause. The NFIP Reform Bill of 1994 (Appendix D, pp. 14-16) provides mitigation grants to those states and communities that have developed mitigation plans that include a comprehensive strategy for implementation. This bill defines grant eligible activities as elevation, relocation, demolition or floodproofing of structures; acquisition of substantially damaged property for public use; provision of technical mitigation assistance by states to communities and individuals; minor physical efforts not duplicated by other federal programs; and other measures determined by FEMA or in mitigation plans.
Findings:
Current regulations provide for effective mitigation of substantially damaged and repetitive loss structures.
Recommendations:
A3.1.3-1 Rely on the present federal, state and local regulations to appropriately mitigate unsafe conditions (e.g., repetitive loss or substantially damaged buildings) within the floodplain.
3.2 STATE
State guidance pursuant to flood hazard mitigation is primarily found in a section of the environmental protection measures of the Coastal Act and the Water Resources Board. The relevant sections of the Coastal Act are provided in Appendix J. Also in this appendix are the relevant portions of the Land Use Plan (LUP). The provisions of the LUP have Coastal Commission approval.
The State Flood Hazard Mitigation Plan allocates federal funding to local governments who are eligible through annexation of their local Flood Hazard Mitigation Plan to the state FHMP. Possible future amendment of the FHMP is mentioned in a letter from the County (Appendix K, p. 17).
recommendations:
A3.2-1 An amendment should be made to the Local Annex to the State FHMP to incorporate the Topanga Creek Watershed Management Plan.
3.3 LOS ANGELES COUNTY
Land use Plan (LUP). The Countyís implementation of the Coastal Act is embodied in the LUP guidelines. The portions of the LUP relevant to flood hazard mitigation are listed in Appendix J.
Building and Safety Code. Los Angeles County ordinances (Appendix K) now in effect include Section 308(a) of the Building and Safety Code, which describes requirements in flood hazard areas and Floodways. This code ties into federal regulation with its citing of FEMA code 60.3. County Floodway mapping accompanied by 308(a) has been the main component of floodplain management in the unincorporated areas. Sixty-one designated Floodways are in place, with four in Topanga Canyon on Garapito, Red Rock and Santa Maria creeks, and near the mouth of Topanga Creek.
An Interim map, based on the DPW estimate of the runoff from their Capital storm, is presently used to make planning decisions along a large portion of Topanga Creek adjacent to the Boulevard. A key problem with this map is that DPW's Capital storm (i.e., a 50-year storm) produces a larger flood than FEMA's 100-year storm. That is, on the Interim map the flood hazard zone is substantially broader than on the FIRM map. Section 308 (a), as it pertains to floodways, places severe restrictions on what may occur in this zone: any change, construct, or item placed in this zone cannot change stream elevations for the 50-year design storm by more than (0.0000) ft. Changes to 308(a) have been proposed by DPW which would include convenants on property and which would allow no outside hydrological analyses [15].
Section 20.94 Channels Ordinance (Appendix K, pp. 3,4) details property owner maintenance responsibilities for clearance of obstructions and regulation of bridges and dip crossings. The DPW proposes to introduce a bridge ordinance based on their Floodway water surface elevations. This proposal would require clear span bridges with setbacks and elevations which may not be feasible for residents to meet due to cost and available land. Moreover, since the most critical of the undersized bridges are those owned by DPW, it would seem that this ordinance is focused in the wrong direction.
The Proposed Topanga Floodway Ordinance (Appendix K, pp. 2-6) is a by reference ordinance comprised of Building Code 308(a), which references Title 44, Section 60.3, Code of Federal Regulations; the Channels Ordinance 20.94; Chapter 11.60 of the County Health and Safety Code titled Floodways and Water Surface Elevations (designated on a series of maps of Topanga Creek that DPW has generated). There is no inclusive single document. The Topanga Floodway Ordinance relies on the single tool strategy of ìno encroachmentî into the designated floodway.
The CRS Repetitive Loss Plan Ordinance (1992) is included as part of the CRS Local Annex to the State Flood Hazard Mitigation Plan Ordinance (1992) and qualifies the County for Federal Mitigation funds. It appears that various elements of a watershed management plan would qualify for funds (Appendix K, pp. 12,15). These CRS Ordinances in conjunction with the NFIP Reform Bill of 1994 and the FEMA minimum requirements would effectively address (i.e., eliminate) the problem of repetitive loss structures.
The Los Angeles County DPW Floodplain Management Plan is a summary of existing laws, codes, ordinances and policies that govern drainage and floodplain management in Los Angeles County (Appendix K). These laws and policies deal with flood control, flood protection districts, assessments, land development procedures, hydrology, and comprehensive plans for special areas, such as Antelope Valley and the Los Angeles County Drainage Area above Long Beach.
Findings:
FEMA and DPW have established different standards for defining the floodplain in Topanga Canyon, with differing maximum water elevations. DPW, under contract to FEMA, also prepared the FIRM map.
An analysis of the various interrelated ordinances, codes, and amendments that have been incorporated by reference into the proposed Floodway Ordinance indicate that regulatory floodways do not provide protection for existing life and property, the community, or the creek environment.
recommendations:
A3.3-1 Adopt the Topanga Creek Watershed Management Plan, which would provide protection for life and property, the existing community and the creek environment.
A3.3-2 Use a more rigorous approach to define the boundaries of the 100 year floodplain (e.g., as described in Section 1.1.1 of Appendix C).
3.4 County designated FLOODWAY
Designated Floodways, which are primarily used in rapidly urbanizing areas and along major rivers [13, 14], are inappropriate in Topanga Canyon, a small rural watershed. They have been principally used to accommodate upland development and are not in keeping with an established creekside community, like Topanga, where many of the community's businesses, roadways, and sensitive flora/fauna are centered around Topanga Creek and its tributaries.
3.4.1 FLOODWAY and flood fringe
Figure A-12 illustrates the difference between the floodway and the flood fringe. The Designated Floodway, while prohibiting any intrusions into the floodway, does allow build out in the flood fringe. As depicted in the figure, this build out must be above the height of the Capital storm. Typically, construction is accomplished by infilling the flood fringe. Inherent in this distinction between floodway and flood fringe is the destruction of the riparian zoneóits flora and faunaóand the piecemeal channelization of the creek. Thus, the concept of Designated Floodway promotes channelization. In contrast, the proposed watershed management plan would preserve the riparian zone and maintain the creek in as natural condition as possible.
3.4.2 historical rationale for the Floodway Ordinance and Maps
The rationale for Floodways in Los Angeles County has been that "with the increasing pressure for individual lots to build structures within the floodplains of major watercourses, establishment of floodways and floodplain water surface elevations is essential to ensure adequate protection to life and property, as well as remaining a participant in good standing in the NFIP. It also ensures Federal disaster relief will be available following a Presidentially-declared flood disaster to repair costly roads and bridges damaged or destroyed in a flood." However, in Topanga there is very little pressure to build in the land adjacent to the creek: fewer than 10 houses have been built over the past 30 years. Secondly, the Floodway Ordinance provides little reduction in the flood hazard because those elements of Topanga most threatenedóthe roads and riparian habitatóare unaffected by the ordinance, and the ordinance does not provide for any reduction in peak flow runoff. Thirdly, participation and good standing in the NFIP does not require the County to adopt Floodway ordinances in preference to other strategies.
3.4.3 Floodway mapping
Since 1990, four versions of a Floodway map for upper Topanga Canyon have been proposed for adoption. Since there have been some significant differences between the alternative maps, this suggests that the mapped flood boundaries have been somewhat arbitrary. In addition, it has not been determined if the 50-year Capital Design Storm, as it is generally applied, could pass FEMA's "reasonable and defensible" criteria [3].
It is understood that a map based on adequate technical data and utilizing sound hydrological methodology is necessary to both community and regulatory decision making. However, this does not mean that a Floodway Map is required. A County Designated Floodway does not reduce the threats to existing homes or lives, and it does not protect the existing, at risk, roadways and riparian habitat.
3.4.4 Impacts of a County Designated Floodway
The true long-term, socio-economic, and environmental consequences of adopting the Proposed Floodway have not been adequately addressed. There seems to be considerable misunderstanding of the impact of Floodways on the Topanga community as indicated by the documents provided by Los Angeles County.
Socio-economic effects. The staff analysis of the Floodway Ordinance provided to the Board of Supervisors stated that there would be ìno fiscal impactî as the result of adopting the ordinance. However, the economic impact for residents and businesses in Topanga would be significant. Structures within the County Designated Floodway, (presumably including County roads and bridges) would have to comply with substantially more stringent building standards (e.g., structural elevations in some locations would need to be substantially increased). This includes any structures to be upgraded or rebuilt, for whatever reason. The result for the creekside community in Topanga would be immediate economic degradation and financial loss. The requirements for rebuilding, following a major disaster of any origin, are prohibitive and make reconstruction extremely difficult. Requirements include caissoned, elevated, or compacted fill foundations; bridges and other structures; and fire access, all of which must be sited above the Capital Storm water surface elevations. The financial burden on the property owner to meet these standards, if indeed they could be met, would be outside the realm of the average Topangan. The normal financial transactions associated with selling or buying property would also be made more difficult because of the general uncertainty regarding rebuilding after a disaster loss. The present democratic mix of people living in the oldest settlement of Topanga (i.e., along the creek) could be eliminated by the economic consequences of the Floodway Ordinance.
Property owners are understandably wary of regulation that could affect the safety and value of their property. Many property owners affected by the proposed Floodway anticipate that their homes and financial security could be imperiled by the imposition of a County Designated Floodway.
Environmental effects. The California Water Code defines floodways as follows:
"A designated floodway is the channel of a stream and that portion of the adjoining floodplain required to reasonably provide for the construction of a project for passage of the design flood, including the lands necessary for construction of
Figure A-12. Schematic representation of a natural floodplain.
project levees." (Chapter 4, Article 1, Section 8402 (F); Coby-Alquist Floodplain Management Act)
A Floodway is therefore, by definition, a regulatory tool for development, concerned with how to develop in the natural floodplain. The regulatory floodway does not address how to maintain the normal hydrological processes of natural drainage courses and how to protect the important riparian and wetland habitat associated with them. Floodways are a tool of urbanizing areas. Land use within the Santa Monica Mountains is not consistent with a scale of urbanization that would require the employment of Regulatory Floodways.
The City of Malibu, which intends to limit urbanization, has rescinded Regulatory Floodways inherited from the County. They adopted the FEMA minimum standard of Federal Regulations Chapter 1, 60.3 (c), as well as a Floodplain Ordinance modeled after the California DWR Model Floodplain Management Ordinance. In contrast, the Santa Clarita area, with 40+ Floodways and 8 more in process, does plan for massive development. In that situation, County Designated Floodways would seem to be appropriate.
In some locations the Floodway Map shows water surface elevations 8 feet higher than that shown on the FIRM maps of the 100 year floodplain. The damage to the riparian zone that would result from elevating bridges and roads to these elevations make it imperative that whatever surface elevations are finally adopted are based on validated models.
Floodways in conflict with community and parks. The National Park Service has testified that Topanga Canyon is a unique cultural landscape in the Santa Monica Mountains National Recreation Area.
"The Topanga community is a living Cultural Resource to be preservedóTopanga is a community apartóa rural community with open space and variety of architecture. Many of the denizens are writers, artists, actors, poets, and working people. The citizens of Topanga, bonded by fire and flood, add a flavor to the Santa Monica Mountains and to Southern California" [23].
There is an inherent conflict between federal agencies in the Santa Monica Mountains and a County Designated Floodway. This conflict is highlighted by the competing goals of two Federal programsóFEMAís program to limit flood losses and the National Park Service's mission to preserve habitat, cultural, and scenic resources. The utmost sensitivity is required to preserve the riparian areas of the Santa Monica Mountains National Recreation Area and to protect the needs of existing creekside residents.
Fairness and equitable treatment. The Topanga Creek Watershed Management Plan seeks to equitably distribute regulatory burdens to all stakeholders in the watershed. The proposed County Designated Floodway would unfairly single out one segment of the community to bear all of the burdens of the canyon's flood hazard. Under the floodway, the creekside community would receive limited flood protection; be deprived of the means to protect itself by sandbagging, berms or other devices; and have put at risk a lifetimeís investment, represented by house and property.
The County can meet FEMA/NFIP participation requirements with the federal 100 year floodplain standard. The TCWMP would propose to exceed these minimum standards through the CRS program. The plan would provide a more balanced, community approach to flood hazard mitigation than the Floodway. The TCWMP would also ensure that not only would the NFIP minimum requirements be met, but that CRS points will also accrue to the County. Insurance benefits and disaster aid would be available to all NFIP subscribers within the County. The County would be eligible for Federal disaster relief following a Presidentially-declared flood disaster, to repair roads and bridges damaged or destroyed in a flood whether under floodway regulation or under a watershed management program.
Receiving "points" from the CRS incentive program to lower residents' insurance premiums (average $21 on a $429 policy premium) is not persuasive to property owners whose properties are devalued and made unsafe by a County Regulatory Floodway. A progressive watershed management strategy in Topanga Canyon that actually reduces the flood hazard is a more appropriate strategy for Los Angeles County to follow in order to receive points from the CRS incentive program.
When the County joined the NFIP Regular Program in l980, affected residents and communities were not informed about the County's intentions to map floodways nor were they informed of the 1980 Negative Declaration for the related environmental impacts. Ignorant of these facts, affected residents subsequently continued to conform with County flood control requirements, based on the FIRM data. These apparent procedural defects have had significant impacts on homeowners who have bought, developed or improved property based on the FIRM maps [15].
Findings:
The proposed Floodway would not accomplish the goals of flood hazard reduction nor provide protection of life and property and natural resources. It is unnecessarily restrictive and creates a clearly disproportionate burden for the existing creekside community in Topanga. At the same time, it accommodates, even encourages, an incremental environmental degradation of the riparian zone.
Topanga Canyon is not a FEMA-designated Floodway.
Eligibility for flood insurance and federally-backed loans for residents and federal disaster relief for infrastructure is NOT dependent on the adoption of a Floodway.
A Designated Floodway would have adverse impacts on the historic residential community along Topanga Creek (comprising some 200 homes on all tributaries), numerous businesses, the infrastructure of roads and bridges, and the riparian environment, with a complex of regulations that:
permit channelization of the riparian zone to meet the requirements for building within the "fringe" area outside the "floodwayî (Sec. 308a). This damages or destroys trees and vegetation and increases the flood hazard downstream.
do not mitigate the physical effects of flooding, siltation and scour since creekside regulation is not complemented by watershed-wide runoff regulation.
deny protection to existing life and property and the environment because of the Floodway requirement that encroachment produce zero (.000) change in water elevations.
single out a segment of the County citizenry who are to receive limited protection from flooding and have limited legal means to protect themselves by constructing flood protection devices.
diminish liquidity and useful life of a property because of onerous building requirements that would be applied should damage, occurring from a disaster of any origin, be assessed at more than 50% of the fair market value (Appendix K, pp. 18-20, tax assessorís statement).
impose interrelated regulations and codes that have the practical consequence that no structure could be successfully rebuilt after 50% damage from fire or earthquake.
are incompatible with CEQA and NEPA due to the impacts on the social well-being of a settled community within an historic landscape and in the SMMNRA [15].
Applying County Designated Floodway regulations in Topanga Canyon will place undue burden upon the affected property owners.
recommendations:
A3.4.2-1 Adopt an environmentally sensitive watershed management approach to flood hazard reduction, which is vital to protect life, property, and the riparian habitat.
A3.4.2-2 Rescind Floodways in lower Topanga, Garapito, Red Rock and Santa Maria creeks and immediately implement the Topanga Creek Watershed Management Plan.
A3.4.2-3 Ensure that the ability to protect existing property by modest and effective means is preserved through employing structures, such as gabion flood walls, that do not create downstream impacts.
A3.4.2-4 Adopt the model California DWR Model Floodplain Management Ordinance using FEMA minimum standards.
3.5 POLICY CONSISTENCY
In developing a watershed management plan, we encountered underlying contradictions in existing policy and regulations pertaining to flood hazard, Public Health and Safety, and drainage. Based on this studyís findings, various recommendations are made on the actions necessary to resolve conflicts.
3.5.1 Stream management
There is a basic conflict between the requirements of the Channels Ordinance and the resource protection requirements of the California Department of Fish and Game, and the Coastal Commission. Clearance of obstructions and sediment in order to reduce the flood hazard may be considered acceptable by Public Works agencies and unacceptable by the resources agencies. Similarly, there are opposing agency views on the various stream crossing techniques (e.g., bridges versus dip crossings).
Responsibility for the physical removal of hazardous creek obstructions between private property owners and pubic agencies is not clearly defined, nor is there an established procedure to implement and enforce the existing regulations pertaining to removal of creek obstructions.
Findings:
Agencies need to have a unified view of appropriate practices within the watershed
The role of the DPW and private property owners with respect to the removal of channel obstructions on private property needs to be established.
Recommendations:
A3.5.1-1 Establish a Watershed Management Committee including representatives of all agencies with jurisdiction within the creek floodplain to establish a common set of development standards and Best Management Practices.
3.5.2 Public health and safety
There are contradictions for public health and safety between the several levels (i.e., federal, state, county) of government with respect to flood hazard mitigation regulations.
Encroachment. Life and property are potentially put at risk by the restrictions on encroachment into the Floodway. Under the Floodway, any encroachment which changes the water level in a Capital storm by more than 0.000 feet would not be allowed. Thus, the Floodway would prohibit the use of sandbags, berms, or other flood protection devices. This contravenes Federal and State regulations that give priority to protecting life and property, and is inconsistent with the Countyís own emergency plans described in the County's Local Annex to the State Flood Hazard Mitigation Plan (FHMP) that specifies the use of sandbagging for flood protection.
The CRS Repetitive Loss Plan recommends a number of retrofitting techniques that require some degree of encroachment to protect existing property. These are described in a series of standard FEMA manuals which are an important part of the homeowner education program for CRS plans. Under the County Designated Floodway, many of the recommendations in these manuals could not be implemented.
Actual practices during flood emergencies are inconsistent with the adopted Floodway regulations. Encroachment regulations have been routinely ignored whenever it has been necessary to protect structures, life and property from flood events. Both private property owners and government agencies have constructed emergency structures that encroach into the designated Floodway. For example, the Santa Monica Mountains Conservancy, a state agency, has constructed a berm (Figure 11) in the Red Rock Canyon Designated Floodway to protect two of its structures. A group of properties in the lower Topanga Canyon area (an area under Floodway Ordinance) were spared damage during the rain storms of February 1992 due to "extensive sandbagging and grading of berms to protect the areaî (FHMP CRS Repetitive Loss Plan, Appendix K, p. 13).
There are reasonable, practicable ways to protect existing property without detriment to adjacent properties. This may be seen at the Topanga Center, an arcade of approximately 20 business operations, where the concept of a flood wall has been successfully carried out and provides flood protection for the on site businesses. It does so in such a way as not to increase the risk to downstream property owners. Moreover, the cost of the wall and the disruption incurred during its construction was minimal. It is important that these solutions to flood hazard mitigation be allowed and that regulation be consistent with the realistic protection measures that are required to protect property during flood emergencies.
Community Safety. Topanga Elementary School is accessed from Topanga Canyon Boulevard across the School Road bridge over Topanga Creek. This is the only vehicular access to the school and on weekdays these roads are traversed by hundreds of cars carrying children to school. According the Floodway maps, Topanga Canyon Boulevard is under water from School Bridge Road to Robinson Road during the Capital storm.
These estimates indicate a profound danger to the children and their parents, and may require the County to prepare an emergency evacuation procedure for the school, a road closure procedure upon warning of an impending Capital storm, and a plan to expeditiously upgrade all of the bridges and raise the road along this segment of Topanga Creek. To alleviate the threat described in the Floodway maps would require a major expenditure of funds to either raise the bridges and Topanga Boulevard or widen and channelize the creek at this location.
It is inconsistent policy to apply stringent regulatory restrictions to private homeowners which are not also met by the County and Caltrans infrastructure for which analysis predicts a significant threat to public safety. This type of inconsistency, which has profound implications for the safety of the community, highlights the importance of accurately assessing the flood hazard in order to develop realistic mitigation measures.
FEMA Mitigation Activities. In contrast to the County Designated Floodway regulations, the following list of Flood Hazard Mitigation Activities, provided by FEMA in their Guidelines for the Community Rating System, provide a more pro-active strategy to reduce flood hazard and associated regulatory conflicts. The proposed Topanga Creek Watershed Management Plan has utilized many of the mitigation activities shown in the Table A-1.
Findings:
The regulations governing encroachment into the floodway are too restrictive and, in some instances, actually threaten public safety.
The CRS program provides many optional activities to reduce the flood hazard that benefit both public and private owners.
Public access and safety is best afforded by reducing peak flow runoff.
Table A-1. Flood hazard mitigation activities suggested by FEMA.
Component
ActivityFlood ControlLevees/Floodwalls
Reservoirs/Detentions
Channel Improvements
Control Gates/Backup Valves
Terracing/Runoff ControlsProperty Protection
Building Relocation/Acquisition
Building Elevation
Flood Proofing
Self-help Advice/ Assistance
Flood InsuranceEmergency ServicesFlood warning
Sandbagging
Evacuation/Rescue
Public Health/Safety MaintenanceFloodplain ManagementPlanning/Zoning
Floodplain Development Regulations
Open Space Acquisition/Easements
Storm Water Management
Stream Maintenance
Recommendations:
A3.5.2-1 Assess flood hazard to the County bridges along Topanga Canyon Boulevard and Old Topanga Canyon Road, and make appropriate emergency plans where required.
A3.5.2-2 Flood Hazard mitigation regulations should be applied alike to private property owners and public agencies.
A3.5.2-3 Use a broader range of options in the CRS program to reduce the flood hazard in order to benefit both public and private owners.
3.5.3 Drainage policy
Drainage compliance is governed by various codes, laws and ordinances but policy apparently follows the California Supreme Court's most recent ruling: in the case of Locklin (Appendix K, p. 22), "reasonable use" is acknowledged to be the County standard for development projects, and is used in urbanizing circumstances where drainage alteration is inevitable. By "reasonable use", drainage from any development site can be directed to a natural drainage course where it does not increase velocity or concentration and does not increase peak flow for the Capital storm. In a steep watershed such as Topanga, this standard promotes flood hazard and constitutes a threat to the public infrastructure as well as to the creekside community.
The County's authority, relative to drainage, is limited to withholding approval of a building or development permit if it creates a flood hazard or is within a flood hazard area (Appendix K, p. 21). The determination of whether a flood hazard is created must be made using a validated hydrologic model to predict stream flows and elevations, as pointed out by Dr. John A. Dracup, an eminent researcher in the areas of hydrologic and hydraulic modeling and professor at UCLA [19]. The Motion of February 11, 1993 (Appendix K, pp. 24-26) made by Supervisor Edelman, which restricts the runoff from new developments to equal that of the pre-developed conditions, was intended to address the concerns of the community with regards to increases in runoff from new developments under all conditions.
Findings:
Significant flood hazards may be created by substantially smaller storms than the Capital storm.
Drainage policy needs to ensure that the flood hazard of downstream properties is not increased under any conditions. Current procedures are not consistent with achieving this goal because they only address peak flows.
Recommendations:
A3.5.3-1 Pre-peak discharges should be evaluated using best estimate models rather than the worst case models used currently.
A3.5.3-2 Downstream property should be protected from increases in runoff due to upstream developments.
3.5.4 Vegetation Removal for Fire Safety
Following the 1993 Old Topanga wildfire, the Board of Supervisors recognized that it was necessary to make changes to the fire and building codes to limit the loss of homes and lives in the high fire hazard areas of Los Angeles County. Based on the recommendations of the Wildfire Safety Panel, the Los Angeles County Board of Supervisors adopted a number of ordinances amending the Building, Plumbing and Fire Codes which became effective on August 13, 1995. Included in the changes was amendment Section 11.702(a) to the Fire Code that required an approved fuel modification plan for all new construction in VHFHS zones. The Fire Department guidelines for fuel modification developed under the new code amendment require that downhill slopes of 0 - 9o[0-20%] be cleared for a distance of two hundred feet; slopes between 9 - 40o[20-40%] be cleared for a distance of two hundred fifty feet; and slopes greater than 18o[40%] be cleared for a distance of three hundred feet.
However, there is a clear and well documented relationship between vegetation removal and slope failures that result in mass movement of soils. These slope failures become common on slopes above 3:1 or 33% [28].
Similarly, there is documented relationship between increased stream sediment loading and increased downstream flood damage. During the 1992 high intensity rainstorms in Los Angeles and Ventura counties, mass movement was common on unvegetated slopes. The sediment loads caused by mass movement from slope failures led to extremely fast rates of stream rising which was identified as the primary factor in causing downstream flood damage [22].
Therefore, houses should be sited in such a way that regulation clearance to protect the structure can be accomplished without creating off-site hazards. This would be consistent with the local area plans that apply to the Topanga watershed. These include: Hillside Management procedures (Ordinance 82-0003) which prohibits vegetation clearance on slopes > 2:1, [Malibu LUP, P150]; non-implemented recommendations in the Malibu/Santa Monica Mountains Interim Area Plan to require standards for firesafe site designations including setbacks from steep slopes, [IAP Implementation Measure 5.5]; and development restrictions in high fire hazard zones [Policy 15, Santa Monica Mountains Comprehensive Plan].
Findings:
Implementing the Fire Department's recommended guidelines for vegetation clearance for new development, without adopting appropriate development standards for the siting of new structures in the high fire hazard zone, will require that significant amounts of deep rooted, drought resistant, mature native vegetation be removed.
Under the new guidelines, the greatest amount of vegetation will be required to be removed from the steepest slopes where it provides the greatest amount of slope stability.
Vegetation removed from slopes will increase the amount and rate of surface runoff and erosion; will increase the amount of mass movement and sediment loading of stream channels; and will cumulatively contribute to downstream erosion and flooding.
There have been no code changes implemented in conjunction with the fuel modification guidelines to mitigate site specific fire hazard factors such as proximity to downhill slopes, time and distance from fire services, and adequate road access to and from the major roads that provide emergency ingress and egress.
Recommendations:
A3.5.4-1 Continue to require that the Fire Department review and approve landscape and fuel modification/vegetation management plans for all new developments and major remodels. No fuel modification plans should be approved that require greater than 30' vegetation clearance on slopes >3:1 (33%)..
A3.5.4-2 Require that the Fire Department and the Regional Planning Department evaluate all fire safety factors that affect the ability of a development site in the Santa Monica Mountains to survive a wildfire including: proximity to downhill slopes; time and distance from fire services; and adequate road access to and from the major roads that provide emergency ingress and egress to the site.
A3.5.4-3 Provide recommendations on zoning and code changes to the Board of Supervisors to allow comprehensive site evaluation of fire safety by the Planning Department, to be implemented in conjunction with the fuel modification guidelines.
3.5.5 Policy summary
The value provided by Topanga Creek, both environmental and aesthetic, is appreciated by the larger community of Los Angeles County as well as the residents of Topanga Canyon. A regulatory program must be viewed and planned for in the context of the whole watershed and must consider and protect against impact in the downstream areas due to upstream development. Protection of Topanga Creek ensures that the infrastructure will adequately serve in a flood emergency, adding to our common goal of safety and protection of citizens.
Contradictions inherent in present drainage policy, public health and safety policies, the County Designated Floodway regulations, and the project approval process can be resolved by developing a watershed management plan. The Topanga Creek Watershed Management Plan combines elements vital to the integrity of the watershed and focuses on reducing peak flow runoff at the source by employing detention basins and ponds, by careful grading and paving, revegetation, and by maintaining the stream channel.
Flexible objective standards and criteria can optimize safety objectives without placing extreme constraints upon property owners and community. Incorporating the CRS program into a watershed management plan provides innovative alternative solutions to the problems of flood hazard reduction and protection of natural resources within our small rural community. The future of floodplain management lies in watershed management with its potential to mediate environmental, legal, and public safety issues. Watershed management will ultimately benefit all levels of government as well as our canyon community.
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