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a. Study Area. The Silver Strand is a relatively narrow sand spit that extends northward from the Tijuana River inlet to the entrance of the San Diego Bay, in San Diego County, California. It separates San Diego Bay from the Pacific Ocean, and includes the shorelines of the North Island Naval Air Station, City of Coronado, the Navy Amphibious Base, Silver Strand State Beach, the Naval Radio Station, and Imperial Beach. The Silver Strand shoreline is located within the jurisdictions of both the City of Coronado and the City of Imperial Beach.

The study area is located along the southernmost stretch of the Silver Strand shoreline that corresponds with the corporate boundary of the City of Imperial Beach southward to the U.S./Mexico international border.

b. Study Authority. The study is a reevaluation of the Federal project authorized by Section 101, Public Law 85-500, River and Harbor Act of 1958, approved July 3, 1958.

“SEC. 101. That the following works of improvement of rivers and harbors and other waterways for navigation, flood control, and other purposes are hereby adopted and authorized to be prosecuted under the direction of the Secretary of the Army and supervision of the Chief of Engineers, in accordance with the plans and subject to the conditions recommended by the Chief of Engineers in the respective reports hereinafter designated: ...San Diego County: House Document Number 399, Eighty-fourth Congress...”

c. Project History. The River and Harbor Act of 1958 authorized construction of a system of five stone groins along the beachfront of the City of Imperial Beach. The plan called for the northernmost groin to be located at the north end of the existing U. S. Naval Radio Station seawall. The other four seawalls were to be constructed southward at intervals of about 305 meters (1,000 feet). The southernmost groin was to be 122 meters (400 feet) south of Coronado Avenue (now Imperial Beach Boulevard). Construction was to start with the northernmost groin and proceed as the down-coast side of each groin filled with sand. Groin Number 1 (northernmost) was completed in September 1959. Groin Number 2 was completed in January 1961. Groin Number 1 was subsequently extended in 1963. The two groins were not effective and construction of the remaining project was deferred.

The City requested that the Corps re-activate the project and investigate alternative means to stabilize and restore the beach. In 1979 the Chief of Engineers approved a Post Authorization Change Report that proposed constructing a submerged offshore breakwater in lieu of a groin system. After award of a construction contract in 1985, a Federal District Court enjoined the project on the basis that significant changes had occurred since the preparation of the Environmental Impact Statement in 1978. The construction was terminated. The authorized project for Imperial Beach was re-classified to deferred category in 1993-94.

d. Problem. The Silver strand shoreline was initially a natural sand spit supplied with sediment primarily by the Tijuana River. Since the construction of dams and reservoirs on the river, the ocean side of the Silver Strand has had to be artificially renourished to combat beach erosion. Currently, erosion is occurring at the Imperial Beach study area, while up-coast locations are accreting.

The City of Imperial Beach shoreline is severely impacted by coastal storms. The report defines two study area reaches--Imperial South reach and the Imperial North reach—based on the existence of coastal protection structures and expected effects of long-term erosion. Local and private interests have installed revetment across the beach face of the majority of the beachfront buildings in the Imperial-South reach. Winter beach erosion leaves the beach depleted of sand with cobbles and boulders exposed. Condominiums located immediately behind the revetment are subject to damages caused by overtopping waves during significant winter storms. Where the revetment ends just south of the development, high tides and winter storms wash debris and sand around the revetment and cause flooding. In the south reach, structures are susceptible to inundation and wave attack only. The study assumes that long term erosion would be arrested at the existing south reach revetment in about year 2007.

Structures in the Imperial-North reach are susceptible to inundation, wave damage, and long term erosion. Generally, revetment or seawalls do not protect older buildings on the shoreline of the Imperial-North reach. Net shoreline retreat along this reach is estimated as 2 meters (6.6 feet) per year. The report indicates that at current rates, the total volume of available sand may be exhausted by 2007, leaving a natural armoring of cobbles and boulders at the shoreline. At that point, the shoreline will be approximately at the first row of coastal development. Shoreline retreat would be expected to slow to about one meter per year at that time. The report indicates that about 30 structures could be lost to long-term erosion by the end of the 50-year period of economic evaluation.

There are 102 residential structures, four commercial structures, and 19 vacant lots along the beachfront of the Imperial—North and Imperial—South reaches. The report cites total equivalent annual damages as $2,054,400 in the absence of the proposed Federal project. This amount includes $867,100 in storm damages to structures and contents, $445,600 attributed to land loss, $391,600 equivalent annual costs for utility relocations, and $350,100 in equivalent annual recreation losses.

e. Report Recommendation. The report indicates that the apparent NED plan consists of constructing a sand-filled beach berm along 2,165 metes (7,100 feet) of shoreline at the City of Imperial Beach. The initial construction would consist of placing 850,000 cubic meters (1,110,000 cubic yards) of sand at elevation +4 meters (13.1 feet) referenced to mean lower low water (MLLW). The beach fill at elevation +4 meters MLLW would be about 23 meters (75 feet) wide. The foreshore would slope from elevation +4 meters MLLW 1-meter vertically for 15 meters horizontally to mean sea level at 0.95 meters MLLW. Based on an estimated long-term erosion rate of 2 meters (6.6 feet) per year, the berm would be expected to erode away in about 11 years. The beach berm would be replaced at that time. Based on this 11-year cycle it is expected that beach berm would be replaced four times during the 50-year period of anticipated Federal participation in the project. Sand would be dredged from offshore borrow areas. A total of 3,400,000 million cubic meters (4,420,000 cubic yards) would be required for the initial construction and four beach berm replacements. The report indicates that the proposed project would reduce storm damages by about 89 percent.

f. Project Economics. The initial construction cost is stated as $5,986,500 at October 2001 prices. Continuing construction costs are shown as $23,946,000. Based on a 50-year period of evaluation and a 6.375 percent discount rate, this plan has equivalent annual costs cited as $789,600. The report indicates that equivalent annual benefits associated with the plan are $1,799,100. Equivalent annual net benefits are cited as $1,009,500 and the indicated ratio of benefits-to-costs is 2.3 to 1.0.

g. Cost-Sharing. The City of Imperial Beach is the prospective non-Federal sponsor of the project. Cost sharing for initial construction of the beach nourishment project would generally be 65 percent Federal and 35 percent non-Federal in accordance with Section 103 of WRDA 1986, as amended. Cost sharing for continuing construction would generally be 50-percent Federal and 50-percent non-Federal.

2. POLICY ISSUES IDENTIFIED BY CESPL FOR DISCUSSION AT THE AFB:

a. District Issue 1 (Authorization): The existing project authorizes the Corps of Engineers to provide shore protection along Silver Strand-Imperial Beach by constructing coastal and nearshore structures for the purpose of shoreline stabilization. The authorized project for Federal improvements is cost shared at a ratio of 57% Federal and 43% non-Federal. The cost sharing for the originally authorized project was 40% Federal and 60% non-Federal. The originally authorized project has been partially implemented, but completion was terminated based on project ineffectiveness. The authorized Federal project was not constructed due to opposition from local environmental interests. The NED plan under the existing GRR effort involves providing shore protection for Silver Strand-Imperial Beach by constructing an initial beach fill project, with periodic nourishment over a 50 year project life. In addition, the currently authorized project’s cost sharing ratio of 57/43 is inconsistent with WRDA 1986, which established a cost sharing ratio of 65% Federal and 35% non-Federal for shoreline protection projects. Since the current GRR study recommends a plan to provide shore protection to Imperial Beach through beach fill with periodic nourishment versus structural solutions as presently authorized, and since the currently authorized project cost sharing ratio is inconsistent with WRDA 1986, SPL recommends the NED plan identified under the current GRR study be implemented under a new authority granted by WRDA legislation.

HQUSACE Review Team Assessment and Recommendation: The policy compliance review team concurs that additional congressional authorization would be required to implement any project proposal that is significantly different from the authorized project. The apparent NED plan presented in the report is completely different from that currently authorized; therefore, implementation would require new congressional authority. However, note that based on the plan formulation presented in the report, the policy compliance review team questions whether the NED plan has properly identified (refer to comments in paragraph 4 of the following). Cost sharing for initial construction of the NED plan would be consistent with that specified in Section 103(c)(5) of WRDA 86 (generally 65 percent Federal and 35 percent non-Federal). Cost sharing for periodic nourishment (continuing construction) would be consistent with Section 215 of WRDA 99, which requires that such costs be shared 50 percent Federal and 50 percent non-Federal. While this represents cost sharing in general, specific project cost sharing may differ based on ownership and use of the shores. The general cost shares apply for developed public or private shores where there is adequate public access and use. For public non-Federal shores, such as a park, the cost sharing is 50/50 and for private non-developed shores the cost sharing is 100 percent non-Federal. Federal shores are cost shared 100 percent Federal (reference ER 1165-2-130 and Appendix E of ER 1105-2-100 http://www.usace.army.mil/inet/usace-docs/eng-regs/cecw.htm ).

District Response: District concurs with HQUSACE Review team’s comments. Implementation of the NED Plan will require congressional authorization. The study area shoreline is 100% Public, non-Federal. Project costs will be shared 65% Federal and 35% non-Federal. Periodic nourishment would be consistent with Section 215 of WRDA 99, which requires such costs to be shared 50% Federal and 50% non-Federal.

Discussion: All agreed that the proposed plan would require new authorization for reasons stated in HQUSACE recommendations.

Action: The GRR will be processed to the Congress for new authorization in a Water Resources Development Act. Project cost sharing is to be based on shoreline ownership, use, and type and incidence of benefits. The project benefits are reduced hurricane and storm damage to public and private property and incidental recreation, see Table 2, page 11, ER 1165-2-130. For those project segments that provide hurricane and storm damage reduction to publicly owned and privately owned structures, 65 percent Federal/35 percent non-Federal cost sharing would be applicable. However, for those segments where the project will protect lands dedicated to park or conservation uses, applicable cost sharing is 50 percent Federal / 50 percent non-Federal. Costs to protect privately owned vacant land would be apportioned 100 percent non-Federal. Composite cost sharing that appropriately considers the type of facilities that would be protected by the project will be shown in the draft report, see Appendix C, page C-1, ER 1165-2-130.

b. District Issue 2 (Ned Plan): The NED plan (Alternative 1A) identified in the study proposes an initial beach fill at Imperial Beach of 850,000 cubic meters, with a resultant beach width of 23 meters. Under this plan, the shoreline would be nourished at a frequency of once every 11 years. Annual net benefits derived from this plan are $1,009,543 at a BC ratio of 2.28. Based on the CCSTWS, San Diego County analysis, the NED plan presupposes a steady shoreline erosion rate. Following initial construction (initial beach fill), at Year 11, the shoreline is predicted to recede to baseline conditions resulting in higher residual damages from wave attack and flooding. Alternative 1B involves an initial beach placement of 2,000,000 cubic meters, providing an initial beach width of 54 meters, with a nourishment frequency of once every 15 years. At Year 15, following initial construction, the protective beach is predicted to erode to 23 meters from the baseline shoreline, thus providing a beach buffer zone of 31 meters between nourishment cycles. The annual net benefits derived from Alternative 1B are $946,247 at a BC ratio of 1.86. Since Alternative 1B results in lower residual damages than Alternative 1A, and embeds a factor of safety by establishing a beach buffer zone between nourishment cycles, and since the annual net benefits difference between the two alternatives is $63,116, SPL recommends the adoption of Alternative 1B as the Federally preferred plan for implementation.

HQUSACE Review Team Assessment and Recommendation: The district recommends adoption of a more expensive plan with lower net benefits than the tentatively identified NED plan. The district notes that the more expensive plan would have a factor of safety by establishing a beach buffer zone. Note that based on the plan formulation presented in the report, the policy compliance review team questions whether the NED plan has been properly identified (refer to comments in paragraph 4 of the following). In general, ER 1105-2-100 requires that the NED plan be identified and recommended for implementation, unless the ASA(CW) grants an exemption to this requirement. A plan that is smaller than the NED plan may be granted a “categorical exemption” and cost shared in accordance with the NED plan if requested by the non-Federal sponsor. A plan that is larger than the NED plan may be recommended as a locally preferred plan (LPP). Paragraphs 4-3b(2)(a) and (b) of ER 1105-2-100 describe the documentation required to support recommendation of a LPP. However, typically the incremental cost of the LPP above the cost of the NED plan would be 100 percent non-Federal. Table 9.2 of the report shows that equivalent costs increase by 40 percent when moving from Alternative 1A to 1B, while storm damage reduction benefits increase by only 12 percent. Table 7.2 shows that all of the increase in storm damage reduction benefits would accrue to the Imperial--North reach of the proposed project (Note comment 4.d below). The table shows that recreation benefits increase by 24 percent. Thus, making the case that the increase in storm damage reduction is “justified” by the increased costs may be difficult.

District Response: The District concurs with HQUSACE Review Team’s interpretation of the policy regarding recommending a project larger than the NED Plan. Responses to comments regarding identification of the NED Plan are addressed in the District’s responses to Paragraph 4 of the following.

Discussion: Corps precedent for shore protection studies traditionally involves maintaining a design beach section with a specific level of protection. Periodic nourishment is sacrificial material to assure that the design beach will be available and integrity of the project is maintained over the period of Federal participation in the authorized project. Accordingly, Plan 1A is not a complete plan and should be eliminated as an alternative plan.

Action: The draft report will be revised to eliminate Alternative 1A as an alternative plan. An appropriate array of alternative plans will be formulated and displayed in the report to demonstrate that the NED plan is properly identified.

3. PLAN FORMULATION AND EVALUATION:

a. Formulation of Hurricane & Storm Damage Reduction Alternatives: The method used to formulate alternatives may not be conducive to proper identification of the NED plan. All alternatives shown in the report include a design section that provides for a 23-meter (75-foot) wide beach berm at elevation +4 meters referenced to mean lower low water. Plan 1A allows the design beach berm to erode away (no advance maintenance), while other alternatives vary the initial fill by including progressively larger quantities of advance maintenance. Typically, hurricane and storm damage reduction plans that employ sand fill are formulated by first determining the economically optimal design section. Normally, this is accomplished by evaluating design sections that vary the width and elevation of the design berm. Also, such evaluations typically consider whether including a dune is appropriate, and if so, what dune crest elevation is optimal. Once the optimum design profile is established, analyses are done to determine the optimum advance nourishment and periodic nourishment schedule. The NED plan is that which optimizes both the design profile and nourishment schedule. Advance maintenance material is considered sacrificial. Its purpose is to help maintain the integrity of the design section over the period of Federal participation in the project. If the design profile is not maintained for the 50-year period of recommended Federal participation, as for alternative 1A, expected damages should vary each year during the period of evaluation. Typically the NED plan design section is identified and maintained for the period of Federal participation rather than allowing different levels of protection for each year of the evaluation. The report must display an array of alternatives that bracket the optimal design section. Consequently, plans that are both smaller and larger than the optimal plan should be developed, evaluated and displayed in the report. Note that shore protection and beach erosion control are not project purposes identified in WRDA 86. Consequently, the project must be formulated to address the hurricane and storm damage reduction project purpose. Thus, the plan formulation should also evaluate viable structural solutions, such as revetments, that may reduce hurricane and storm damages.

District Response: The study’s coastal engineer and economist determined jointly that a 23-meter beach width was the minimum beach width required to protect residential and commercial properties against a 100-year storm event. Following receipt of HQUSACE comments, additional beach widths were analyzed to identify the optimized design section. Design beach widths of 12-meters, 23-meters, 25-meters, 34-meters, and 54-meters were analyzed. The 25-meter beach width, the initial width at which zero damages related to wave attack and inundation from run up will occur, resulted in the maximum net benefits. Varying the berm height to optimize the design beach section was not evaluated, as it is the position of the District that the current design height of +4-meters MLLW mimics the natural summertime beach configuration within the study area and thus will maximize the functionality of the beach fill project. Additional details regarding beach width and height optimization will be covered in responses to comments regarding “Dune and Beach Width Alternatives” and “Predicted Project Performance”.

Alternative 1A consists of maintaining the baseline shoreline by initially providing a 23-meter wide beach. The 23-meter wide beach would erode to the baseline conditions in 11 years. Therefore, this plan calls for periodic nourishment every 11 years. The disadvantage of this plan is that it provides varying levels of protection. The initial placement provides 100 year level of protection; however, expected damages increase each year prior to renourishment as the beach width erodes.

Plans 1B, 1C, and 1D maintain the shoreline at the baseline + 23-meters. All of these plans provide 100 year level of protection throughout the project life. These plans differ only in the amount of advance nourishment to be placed. Plan 1B provides for 15 years of advance nourishment; Plan 1C provides for 22 years of advance nourishment and plan 1D provides 50 years of advance nourishment.

Section 4.5 of the Main Report addresses viable structural solutions including groins, revetments and detached breakwaters. These alternatives were studied in depth and documented in a reconnaissance report dated December 1995. That report indicated that these structural solutions were not justified economically. In addition, there was no public support for these types of solutions. Therefore, these alternatives were screened out during the preliminary plan formulation (F-3) phase of this GRR. The draft report will include a more detailed discussion of the investigations conducted during the reconnaissance phase study.

Discussion: HQUSACE representatives explained that Principles and Guidelines requires the Corps to consider a full range of alternatives to support the identification of the NED Plan and that the Plans 1B thru 1D were the same plan with different periods of periodic nourishment. Also see issues 1b. above and 2b below. The District explained the rationale with respect to not looking at alternative beach elevations. A beach lower than natural section will cause depressions and ponding in backshore section of berm, higher berm elevations will result in erosion scarp which is unacceptable. The district pointed out that the current coastal engineering manual recommends building to the natural berm elevation since the beach will seek its long term equilibrium. HQUSACE staff is satisfied with explanation regarding berm height being a single elevation and that the beach design is associated with varying beach widths. However, HQUSACE staff stressed that not evaluating alternative berm elevations is a departure from basic plan formulation principles. It was agreed that the district would revise the draft report to clearly explain and provide the supporting rationale for the basis for alternative protective beach designs including the berm elevation, berm widths and slopes. Also, the district will explain why providing protection to storms greater than a 100-year storm return frequency was not included as part of the formulation and analysis.

Action: The draft report will be revised to clearly explain and provide the supporting rationale for the basis for alternative protective beach designs including the berm elevation, berm widths and slopes. The report text should note that Corps projects are NOT formulated to satisfy an arbitrary level of protection. Basic planning practice requires that arbitrary constraints to plan formulation be avoided. Contrary to the district response, there is no minimum level of protection that must be addressed. Instead, a comprehensive array of alternative designs must be formulated such that the plan that maximizes net benefits (the NED plan) can be identified regardless of the level of protection that it may provide.

b. Dune and Beach Width Alternative: The report does not address alternatives for dune development or optimization of the beach width, which would remain throughout the period of analysis in between nourishment cycles. Therefore, it is not clear that the formulation has identified the NED plan. The draft report should address varying designs for beach width and the feasibility of dune alternatives to assure that the NED plan has been identified.

District Response:

Beach Width: Through analysis of inundation and wave forces within the study area, it was predicted that a 23-meter wide beach, added to an existing varying base year beach width of 10 to 25-meters, would provide the minimum base width necessary to protect against almost all storm damages. The analysis revealed a 23-meter wide beach fill project would result in minor inundation damages and zero damages from wave forces for up to the 100-year storm event. Table 5 in the Coastal Engineering Appendix (Appendix B) displays the expected extreme value for shoreline retreat for storm return periods ranging from 1 to 100 years. For the 100-year storm event, Table 5 (land loss damage category) predicts a 31-meter shoreline retreat. It was calculated based on this retreat analysis that a minimum 23-meter wide beach fill project (on top of a base year beach of 10-meters) will be adequate to protect against damages associated with storm induced erosion and simultaneous wave attack from a 100-year event. Based on HQUSACE comments, an optimization analysis of protective design beach widths of 12-meters, 23-meters, 25-meters, 34-meters and 54-meters was accomplished. The optimization analysis revealed maximum net benefits are derived under the 25-meter beach width plan. The accompanying table displays the cost and benefit relationship of the five (5) analyzed plans.

Dune Elevation: Naturally formed dunes exist in very few beaches in California. In the case of Imperial Beach, no natural dune exists. Dunes provide protection against hurricanes and high storm surge that is typical on the east coast. This is not the case for the west coast at Imperial Beach. Imperial Beach is not susceptible to hurricane storms and high storm surge; therefore, the District concluded that dunes would not be considered as part of the design cross section. However, a berm elevation of +4-meters MLLW was selected for the design section, as this elevation closely corresponds to the natural berm elevations found within the study area. Elevations greater than +4-meters MLLW would result in berm instability and berm scarping, which may adversely impact recreational opportunities and potentially negatively impact the spawning cycles for grunion. Additionally, higher and steeper berms may result in cost inefficiencies associated with accelerated erosion. Berm elevations less than +4-meters MLLW will result in large beach areas inundated to the combination higher tidal cycles and the higher frequency storm events (MHW for this area is 1.52-meters and H_s for a return period of 2-years is 4.2-meters), and possible ponding as a result of overtopping waves and runup, and again with potentially adverse impacts to spawning grunion. In addition, the berm elevation of +4-meters MLLW for the design beach fill cross-section is consistent with EM-1110-2-1100 (Part V), which states “design berms should generally correspond to the natural berm crest elevation”.

BEACH OPTIMIZATION PLAN

Discussion: The draft report will need to be revised to present the results of the district’s optimization of the design beach. In addition, to demonstrate that a full array of alternative measures considered, the district will revised the report to include information from the reconnaissance study on other alternatives considered and explain why they were screened from further analysis. The district also explained the difference in design storm water levels and how they differ from differ between the East, West and Gulf coasts. In the draft report the district will include discussion of the design storm levels and levels how they differ from the East, West and Gulf coast areas. Also see discussion for issue 2b and 3 a.

Action: The draft report will be revised to include information from the reconnaissance study on other alternative plans considered and provide reasons why other alternative plans are not viable and were not considered for further study during the feasibility phase. The draft report will also address the design storm water levels and explain how they differ between the East, West and Gulf coast areas.

c. Advance Nourishment: It is not clear how the report analyses are addressing advance nourishment as part of the beach fill operations. Advance nourishment is normally included in the initial construction volume to assure that the level of benefits claimed in the economic analyses for a particular beach profile are achieved during the period between nourishment cycles. The analysis in the report appears to formulate varying beach fill widths and volumes as a means of optimizing the nourishment cycle, with the nourishment cycle being determined by the time required for the beach to return to an arbitrary 23-meter width. The district should clarify in the draft report the extent to which advance nourishment is being proposed and the extent to which project benefits would vary between nourishment cycles.

District Response: Concur. The District has accomplished an analysis to optimize the cost effectiveness of the advance nourishment cycles and to optimize the benefits for the total project (protective base beach plus the advance nourishment cycles). The analysis concluded that the most cost effective renourishment frequency is once every 10 years, and involves placement of 760,000 cubic meters of sand to create a 20-meter wide advance nourishment beach. The benefit analysis of the total project plans concluded that the plan for a protective base beach width of 25-meters with an advance nourishment cycle of once every 10 years is the optimal total project. The following tables display the annualized cost comparison for various renourishment frequencies and the annual net benefits for the total project plans.

ANNUALIZED COST FOR RENOURISHMENT FREQUENCIES:

ANNUAL NET BENEFITS FOR THE TOTAL PROJECT PLANS (Base Beach Widths vs. Renourishment Frequencies):

Discussion: The draft report will be revised to include the information in the district response to support the recommended periodic nourishment period.

Action: The draft report will incorporate the development of the periodic nourishment frequencies including rationale for volumes of nourishment. The district will ensure that sufficient data is presented in the draft report to support the conclusions.

d. Incremental Evaluation: The plan formulation should include an incremental evaluation of the feasibility of protecting the Imperial--north and Imperial--south reaches individually. While the report indicates that the minimum project length that is economical to construct covers both the north and south reaches, analyses should be provided to support this assumption. Tables 3.3 and 3.7 indicate that all erosion damages (structures, land loss, and utility relocations) are attributed to the Imperial—North reach. However, table 3.8 shows utility relocation damages equally distributed between the Imperial--North and Imperial--South reaches. This apparent error should be corrected in the draft report. Information shown in table 3.8, when corrected, indicates that only 9.6 percent ($164,000) of the total equivalent annual hurricane and storm damages ($1,704,300) is attributed to the Imperial--South reach, while 90.4 percent ($1,540,300) is attributed to the Imperial-North reach. This suggests that a plan that would provide an equal level of protection to both reaches is not optimal. This should be addressed in the draft report.

District Response: The entire project area from the northern limit to the southern limit totals approximately 1.5 miles. The study area was split into 2 reaches to account for the difference in beach profiles. A rubblemound revetment fronts the south reach while the north reach is a planar beach. It is not engineeringly feasible to build a protective berm in the North reach without having it tail off significantly in the south reach.

In response to HQUSACE “Incremental Evaluation” comment that the analysis should include an incremental evaluation of the feasibility of protecting the Imperial-North and the Imperial-South reaches individually, the District computed the volume needed to build a project that only protects the Imperial-North reach and compared it to a project that would protect both the Imperial-North and Imperial-South reaches. The District took a conservative approach in analyzing the incremental benefits for inclusion of the south reach. The District only included the major damage categories of inundation, wave attack and erosion. The benefits, shown in the following table, exclude recreation, clean up and utilities relocation. The analysis concluded that the incremental cost for Imperial-South is justified.

Discussion: The response to this comment does not display the data to support the results as presented in the table. However, the methodology and results appear to be reasonable.

Action: The draft report will present the results of the incremental analysis. The draft report will be revised to include appropriate supporting data to demonstrate the incremental area for the south reach beach is incrementally justified.

e. Predicted Project Performance: The report indicates that each of the alternatives eliminates all inundation or wave attack damages in the Imperial--south reach. This does not seem reasonable, particularly for alternative 1A since damage potential should increase each year after the initial sand placement. For this alternative, damages should approach without project conditions immediately prior to renourishment. Also, the assumption that all inundation or wave attack damages would be eliminated raises the question of whether a smaller berm width would reduce project costs without significantly impacting benefits. This issue should be addressed in the draft report by formulating and evaluating an array of alternatives, with different berm widths / elevations, for each project reach.

District Response: The district concurs that damage potential in the south reach for Plan 1A should increase each year between sand placement. Our without project conditions model for the south reach accounts for damages as the beach in front of the revetment erodes. By 2007, our analysis shows that no beach exists in the south reach. At that point, wave attack and inundation damages start to occur. Since Plan 1A fixes the beach at the base shoreline, this assumes there is some beach in front of the revetment. Therefore, no wave attack or inundation damages occur.

Discussion: The State of California expressed concern that south beach revetment is not engineeringly designed and in the long term could fail. The district agreed it would address the State’s concern by considering that under without project conditions maintenance of the revetment will be required to assure that the revetment is effective. As discussed in earlier comments Alternative 1A has been eliminated from further consideration. In addition the district explained that for beach widths larger than 25 meters there is zero residual damages as a result of limitation of maximum design storm due to depth limited wave and tide elevations, as well as runup dissipation.

Action: The draft report will explain why the district does not expect any residual damages to occur for design beach widths of 25 meters and larger. This should include information to also address the south beach experiencing wave attack and inundation. The cost of maintenance of sections that are revetted will be developed and presented in draft report. The district will determine the benefits associated with avoidance of these maintenance costs and include them in the evaluation of alternative plans. In addition, Table 5, Appendix B, page B-11, indicates that the storm with a 1-year return period would be expected to produce 8 meters of storm induced erosion. Similarly, about 31 meters of storm induced erosion would be expected to occur given the 100-year event. Based on the data in Table 5, the expected (probability-weighted) annual storm induced erosion is 16.8 meters. Typically, not all of the material removed from a beach during a storm is lost from the system. Material displaced immediately offshore may be re-deposited on the beach during a post storm period. Nonetheless, the report should address the apparent disparity between the assumed 2 meter per year average long-term erosion rate and the suggested 8 meter erosion rate associated with the 1-year return period storm. Given the data of Table 5, the report should explain why the evaluation predicts zero residual damages for the with-project condition.

f. Significant Wave Height: Table 2.2 on page 2-10 shows that the significant wave height is expected to be nearly identical for the 25-year through 100-year events. It is not clear why this would be the case given the change in tidal conditions, wind severity, and wave propagation that would be expected for the more severe events. An under estimate of wave heights for significant events could lead to inaccurate estimates regarding the physical and economic performance of the alternatives and has potential to impact the NED plan selection. The district should review the significant wave height analysis to verify that the appropriate values are being used.

District Response: The wave climatology for the extreme wave analysis was developed based on hindcasts of 34 severe storm events during the period 1904-1988. The hindcast data set was transformed to the project location accounting for island sheltering, refraction, shoaling, and depth limitations. Wind driven water level superelevation (set-up) tends to be small in Pacific Ocean wave analyses and thus is not a governing factor. In the Los Angeles District, extreme value wave analysis typically assumes a mean higher high water tide elevation. Wind severity is also not a critical factor as severe waves are generated by distant storms and propagate as swell, compared to wind severity considerations in a hurricane-based extreme wave analysis. The shallow water extreme value statistical analysis results in a set of waves representative of various recurrence intervals. The significant wave height values are nearly identical for the 25-100 year recurrence intervals which is a direct result of the fact that wave heights in excess of 6.2 m were depth limited due to wave breaking considerations.

Discussion: Clarification was provided by the District regarding the depth limited aspects of the waves generated between 25 to 100 year storm events. The district will provide information in the draft report to explain the depth limited aspects of the waves generated 25 to 100 year storm events.

Action: The draft report will include information and discussion to support the depth limited aspects of the waves generated between the 25 to 100 year storm events.

g. Sand Borrow Sources: Paragraph 4.7 discusses two offshore borrow sites considered as potential sources of sand fill. However, previous text discussions on page 2-5 indicate that while the Imperial Beach section is experiencing significant erosion, the Coronado reach to the north is experiencing significant accretion. Since the material accreting in the Coronado reach is being carried by littoral forces from the Silver Strand and Imperial reaches to the south, it may be economical to consider back passing sandy material from the Coronado area as a borrow source. The district should expand the formulation analysis to address the potential to back pass material in order to assure that the most economical borrow source has been identified.

District Response: The shoaled area near Coronado beach and near Zuniga Jetty was looked at by the Geotech Branch initially during the early phases of the study as a possible source of sand for the project. After some rough calculations into the cost of dredging the area and cursory analysis of sediment sizes at this borrow area, it was not further considered during the study. There are two main reasons why:

1. This area is more than 3 miles away from the beach site. During the study it was recognize that 3 miles or so seemed to be the cut-off for consideration of borrow areas, since the cost for dredging goes up as at a greater distance from Imperial Beach, especially at a distance of greater than 3 miles.

2. The composite grain sizes for the Coronado/Zuniga Jetty borrow area did not fit the grain size composite envelope for the Imperial Beach site. In other words, the grain sizes for sediment in this borrow area were too small when compared to the sizes needed to maintain the beach, i.e. they were not compatible with the Imperial Beach site. The sediment is also of too low a density to maintain the profile at Imperial Beach, i.e. it would wash away faster than a borrow site with larger grain sizes.

Discussion: The district response resolves the concern.

Action: The draft report will include the information contained in the district response.

h. Independent Technical Review: The certification of independent technical review notes that an independent District team completed technical review for the project proposal. The geo-technical report suggests that the Los Angeles District has a “limited history” with hurricane and storm damage reduction projects. Consequently, we recommend that the District seek advice of the Philadelphia, Wilmington, or Jacksonville District in regard to state-of-the-art plan formulation and design of hurricane and storm damage reduction projects. The report makes reference to the Corps’ Shore Protection Manual (SPM). Current coastal engineering practice has gravitated toward equilibrium profile analysis in order to determine the volume placed, and the benefits realized. This is a more conservative design than the use of overfill factors advocated in the SPM. The new Coastal Engineering Manual (CEM) (Draft EM 1110-2-1100) being developed by the Waterways Experiment Station uses this new technique. Refer to the WEB site for the CEM: http://bigfoot.wes.army.mil/cem026.html for additional details.

District Response: This analysis consulted extensively with the Philadelphia District, New York District, San Francisco District, FEMA, and North Carolina Sea Grant. In fact, the main technical criteria for determination of wave force damages was obtained from a study conducted by the Philadelphia District (see Appendix A, reference USACE-PD 1992). This study used many technical references including the Shore Protection Manual and the draft Coastal Engineering Manual. However, this study relied primarily on the Coast of California Storm and Tidal Wave Study (CCSTWS). The CCSTWS was conducted by the Los Angeles District and evaluated decades of measured data to quantify historic shoreline and profile change. These analyses are considered more accurate and representative than any generalized calculations for long-term shoreline change.

Discussion: HQUSACE strongly recommends the Los Angeles District coordinate plan formulation and design efforts with other districts, i.e. CESAJ, that have been successful in implementation of shore protection/beach fill projects. These Corps districts have developed computer models (i.e. COSTDAM, GRANDUC), while not perfected, that successfully integrate the engineering and economic aspects of hurricane and storm damage reduction projects. Information on COSTDAM is provided as an attachment to this guidance memorandum.

Action: The study team will continue to coordinate and get information from other districts as needed.

4. HURRICANE AND STORM DAMAGES:

a. Long-term Erosion Damages: In Table 3.3, projected erosion damages in the north reach are almost $600,000 per structure in year 10 and over $2.1 million per structure in year 15. More specific discussions should be included in the report to support these significant levels of impact. The value of contents within a structure would be expected to be minimal when structural failure due to long-term erosion is eminent. Consequently, support should be provided for why significant content damages have been included for the long-term erosion damage estimates. Further, it may be more reasonable to assume that structures that can be moved from the shoreline would be, rather than be lost to long-term erosion. The evaluation should document that structures assumed to be lost to long-term erosion could not be moved from the shore or protected in place.

District Response: Data in the Table 3.3 was verified with the erosion damage model. In year 15 the total number of structures destroyed should be 6 and in year 20, 7 structures (corrections will be made to the appendix after the AFB). These changes reduce the average damages per structure in year 15 to a little over $1 million per year, and almost $240,000 per structure in year 20. The significant level of impacts in years 10 and 15 are due to large structures being destroyed. For example in year 10 a beach-front motel is anticipated to be destroyed along with 2 apartment buildings. In year 15, three condominium complexes are destroyed (including a major 50 unit complex).

The District concurs that some small percentage of contents may be moved prior the structure being lost to long-term erosion. However, the District has observed that along other erodible stretches of the southern California shoreline, residents continue to inhabit structures that are at risk to imminent collapse. These residents have made no attempt to safely secure valuable contents from the risk of catastrophic structural failure. Per HQUSACE recommendation, the District will re-evaluate the use of 50% content to structure ratio for erosion damages. The draft report will be updated to include either additional support for the ratio that was used, or a description of the rationale used to apply a different ratio.

Discussion: HQUSACE expressed concerned with the reasonableness of the assumption that no action would be taken by property owners to reduce damage with some kind of improvement. HQUSACE staff asserts that a reasonable economic assumption would be that some improvement would be made especially for the high value complexes. District countered that there are no definite programs for the City or State that guarantees protective improvements will be implemented. HQUSACE indicated obvious work had been done in the past by individuals and collective property owners to protect their assets with revetments and bulkheads, as well as with beach nourishment. District noted that past beach fills were opportunistic and related to Federal activities (such as the Navy’s home porting project). The district does not believe any new features will be implemented within the foreseeable future, nor does the district believe that opportunistic beach fill projects can be predicted and counted upon under future without project conditions. The State declared that they would implement protective beach fill projects only if they could leverage Federal funds to assist in constructing such projects. The City declared that reach wide beach fill projects could not be implemented by the city or private parties because of the construction costs, and thus this kind of protective project would require state and/or Federal participation to construct. Additionally, State and City officials indicated that the California Coastal Commission policy is against placement of protective structures seaward of existing tide lines, and that any emergency actions or permitting to protect an individual’s property will require an “after-the-fact” regular permit, to include open ended mitigation of the installed structure. Because of the potential costs, such open-end commitments are generally avoided by individual property owners, and may be sufficient cause for an owner or development to not take action to protect his structure against potential storm induced damages. This comment was confirmed as valid by the staff of the California Coastal Commission following the AFB conference. Based on this additional information/clarification from the State, City and district representatives, it was agreed that it would be reasonable to expect that non-Federal interest would take no action under without project conditions. It was recognized, however, that the district would need to revise the draft report to provide complete support for this without project condition. This will include State laws, policies, regulations, precedents, and/or examples to support no action, other than soft measures.

Action: The draft report will be revised to include appropriate documentation to provide complete support for selection of the without project condition. This will include State laws, policies, regulations, precedents, and/or examples of other limiting factors to support no action, other than soft measures.

b. Derivation of Storm Damages: It is not clear how inundation and wave attack damages were derived or how such damages are expected to vary for each year of the economic evaluation. The economics appendix should include detailed explanations and examples of the derivation of the damages cited. This information should include a schedule (listing) of expected damages by damage category for each year of the economic evaluation. Damages should be shown individually for the Imperial—North and Imperial—South reaches.

District Response: For inundation damages, coastal engineering supplied inundation depths for the related to various storm events and beach configurations for the selected years throughout the study period. FEMA depth damage curves were used to estimate the dollar value of damages to structures and contents. It was assumed that until the structure was destroyed by either erosion or wave attack, it would be susceptible to inundation damages through the study period. Coastal Engineering determined, based on the critical force of the waves, when structures would be 100% destroyed by wave attack. Our analysis of wave attack assumed no damages until the wave force reached a critical force that would destroy a structure.

The economic appendix will be updated to include detailed explanation and tables showing damages by reach and category. Provided as an attachment is a flow chart sketch displaying the logic of the economic damage model.

Discussion: A flow chart outlining the districts rationale in deriving storm damages was presented and the district provided a detailed description of each step of the derivation process. It was agreed this information should be included in the draft report’s supporting appendices.

Action: The draft report will provide a better description of the model and the supporting appendices will provide an example on how the model works on several sample structures, including the north and south reach.

c. Double Counting: It is not clear in the report how double counting of damages is avoided for the inundation and wave attack categories. Further explanation should be provided.

District Response: Wave attack damages were based on the probability of a storm event occurring in any given year that would destroy a structure. Therefore, in any given year there is a certain probability that the structure would be destroyed by wave attack. Conversely, in any given year there is a certain probability that the structure still exists. That “probability of existence factor” from the wave attack analysis was imported into the inundation damage model to calculate future inundation damages. Thus avoiding double counting.

Further, if erosion undermined the structure in any given year, that structure would be removed from the inventory. For example, if wave attack was expected to destroy a structure in year 10, but, if erosion destroys the structure in year 5, wave attack damages were only claimed for the first 4-years. A more detail explanation of damage determination will be added to the draft report.

Discussion: The district response resolves the concern.

Action: The draft report will include further explanation and clarification to explain how damages were determined and why there is no double counting of damages.

d. Utility Relocation Damages: The report indicates that as land is lost through erosion, underground utilities in the Imperial--north reach will be vulnerable to damage or destruction. To avoid this damage, the city will move all the utilities inland to a less vulnerable and more secure location under the without project condition. The first cost of these relocations is $16.7 million. The relocations are to be completed in stages over a 5-year period starting 15 years into the study evaluation period. The economic rationality of these expenditures should be discussed to include why the city would not try to protect rather than relocate the utilities. The total investment cost for the apparent NED plan, which includes the present value of periodic nourishment for the protection of both the north and south reaches, is only $11.8 million. Clearly, the city could protect only the Imperial—North reach at considerably less cost to avoid the assumed $16.7 million in relocations. The avoided relocation costs should not exceed the cost of protecting the north reach only. Verify that this is the case. Further discussion should be provided to support the economic rationality of the without project expenditures of the magnitude assumed in the north reach.

District Response: District contacted City officials after receiving this review comment. City officials stated that the utilities are owned by several different entities: SDG&E, Cox Cable, Pac Bell and Cal AM Water. Costs shown to relocate these utilities will thus be shared. Therefore, the $16.7 million total relocation responsibility and cost to move all of the utilities will be assumed by multiple entities, other than the City.

Discussion: The report will need to include more information regarding the relationship of utilities to the shoreline and assumptions related to when the utilities would be relocated. In addition, the district will include documentation regarding the assumption that the local utility companies will be responsible for relocating their utility lines.

Action: The draft report will include information regarding the relationship of utilities to the shoreline and assumptions related to when the utilities would need to be relocated. Documentation supporting the assumption that the local utility companies will be responsible for relocating their utility lines should also be included.

e. Land Loss: The report includes a $445,600 benefit for land losses avoided in the north reach. The report does not provide any specifics on the quantity or value of the land lost. Further information and discussion is needed to support land loss benefits claimed.

District Response: Concur. Details will be added to the post AFB draft. In summary, the Real Estate sections provided land values for non-ocean view property ($75.00 per sq. ft) this was multiplied by the square footage (approximately 274,000 square feet) of the parcel expected to be impacted by erosion. Starting in year-ten of the study period through year-fifty.

Discussion: Concern is resolved.

Action: The draft report will include information in the district response in further support of land loss benefits claimed. The report will document that a, non-ocean view, 5,000 square-foot (50 by 100) lot would be valued at $375,000 ($75 x 5,000).

f. Storm Damage History: Based on the information in the report, there have been two significant storms over the last 40 years. The 1952-1953 storm resulted in shoreline recession and $25,000 in damages in 1953 dollars. The 1988 storm resulted in $165,000 in damages and $100,000 in clean-up costs in 1988 dollars. It would be helpful to know the approximate return period for these storms. Given the limited storm and erosion damages actually documented in the past, the estimated without project damages appear excessive and should be further discussed and supported.

District Response: During each major storm event that has occurred at Imperial Beach, 1953, 1983 and 1988, there has been some width of dry beach, as a result of natural conditions and limited beach nourishment activities, that has provided protection against storm damage. However, our without project condition assumes no new nourishment over the period of analysis. As the shoreline erodes, the damage potential will increase. The draft report will include a more detailed discussion.

Discussion: As discussed in comment 3e there appears to be an inconsistency between historic beach loss and shoreline retreat data presented in the Coastal Engineering Appendix, Appendix B Table 5, page B-11. The district should review the data to ensure to there are no inconsistencies between historic beach loss and shoreline retreat data for various return periods.

Action: The draft report will include documentation supporting that the beach is retreating. The district will also review the data to ensure to there are no inconsistencies between historic beach loss and projected shoreline retreat data for various return periods.

5. PROJECT COST SHARING:

a. Cost Apportionment: Paragraphs 6.2, 6.3, and 6.3.1 cite requirements of Section 101 of WRDA 86 as applicable to cost sharing for the proposed project. This is not correct. The requirements of Section 103(c)(5) of WRDA 86, as amended by Section 215 of WRDA 99, are applicable to sharing the initial construction and continuing construction costs of the proposed project. Generally, initial construction costs are to be apportioned 65 percent Federal / 35 percent non-Federal. In general, continuing construction costs are to be apportioned 50 percent Federal / 50 percent non-Federal. These percentages are to be modified to account for shoreline access, ownership, and use. Additionally, paragraph 6.3.1 cites a requirement for the non-Federal sponsor to repay 10 percent of project costs, with interest, over a period not to exceed 30 years. This is not correct. There is no repayment requirement associated with sharing the costs of hurricane and storm damage reduction projects. The draft report should provide correct cost sharing citations and show appropriate cost sharing as required in law. Refer to Appendix E of ER 1105-2-100.

District Response: Concur. The data contained in Chapter 6 is in error. Cost sharing discussion in Chapter 8 supercedes the information contained in Chapter 6. The report will be revised to include the correct cost sharing apportionment.

Discussion: The district will review ER 1165-2-130 to delineate cost sharing apportionment for various land uses. Chapter 6 in its current form should be removed.

Action: The district will review ER 1165-2-130 to delineate cost sharing apportionment to account for shoreline access, ownership, and use. Also see action item for comment 5c. Chapter 6 in its current form will be removed and revised accordingly to address this and subsequent comments.

b. Cost Apportionment: Paragraph 6.4 shows the net present value of the estimated first cost and four future berm replacements ($11,821673) apportioned 35 percent Federal ($4,137,586) and 65 percent non-Federal ($7,684,087). This is in error. See the preceding comment.

Discussion: See comment 5a above.

Action: See comment 5a above.

c. Cost Sharing Percentages Must Be Adjusted To Account for Ownership and Use: For the previously authorized submerged breakwater project cost sharing was determined based on the shoreline ownership. At that time, 700 feet of shoreline was owned by Federal agencies, and 4,300 feet was owned by non-Federal public agencies. Further, the current report indicates that there are 19 vacant lots along the beachfront. The draft report must clearly delineate current shoreline ownership and use for purposes of determining the appropriate cost sharing for the project. Refer to ER 1165-2-130.

District Response: The draft report will clearly delineate the current ownership of the shoreline. The study area shoreline is currently 100% Public, non-Federally owned.

Discussion: See comment 5a above.

Action: Note that project cost sharing is to be based on shoreline ownership, use, and type and incidence of benefits. The project benefits are reduced hurricane and storm damage to public and private property and incidental recreation. For those project segments that provide hurricane and storm damage reduction to publicly owned and privately owned structures, 65 percent Federal/35 percent non-Federal would be applicable. However, for those segments where the project will protect lands dedicated to park or conservation uses, applicable cost sharing is 50 percent Federal / 50 percent non-Federal. Costs to protect privately owned vacant land would be apportioned 100 percent non-Federal. Composite cost sharing that appropriately considers the type of facilities that would be protected by the project should be shown in the draft report. Also see comment 5a.

d. Sunk PED Expenditures: Prior (sunk) PED costs, including costs of past and current studies that have not been subject to cost-sharing, should be included in total cost of the recommended project proposal. Including sunk PED expenditures in the total cost of the recommended plan would not effect economic justification. However, sunk PED costs must be included in the estimated of total cost for purposes of cost apportionment.

District Response: Concur. Sunk PED costs will be included in the tables and discussion regarding cost apportionment in the draft report.

Discussion: The district noted that there have been prior PED costs associated with the currently authorized study, in which the local sponsor has met the obligations for their share of these costs. However, as of this date, the cost for the GRR has been completely borne by the Federal government. The district and the non-Federal sponsor believe there is justification to consider these sunk PED costs a Federal responsibility and consequently, the district has requested it be allowed the opportunity to prepare an issue paper presenting their case regarding whether or not the GRR cost should be considered sunk costs at 100% Federal responsibility for the proposed project under new authority.

Action: The district will include sunk PED expenditures in the total cost of the recommended plan. Even though sunk PED expenditures would not effect economic justification, these costs must be included in the estimated of total cost for purposes of cost apportionment. The district will prepare and submit an issue paper to HQUSACE regarding whether or not sunk PED costs should be cost shared. The issue paper will be used as a basis for HQUSACE reconsideration of guidance related to treatment of sunk costs.

6. ECONOMIC EVALUATION:

a. Current Federal Discount Rate: The text on page 3-11 indicates that the economic analyses were conducted using a discount rate of 6.375 percent. The appropriate discount rate for FY02 is 6.125 percent in accordance with the Economic Guidance Manual published annually by HQUSACE. The district should update the economic analyses to show the appropriate discount rate in the draft report.

District Response: Concur, post AFB draft will include updated numbers based on current discount rate.

Discussion: Concern is resolved.

Action: The draft report will include updated numbers based on the current discount rate.

b. Interest During Construction: Table 5.1 on page 5-1 shows that interest during construction is being computed for the future nourishment cycles in years 12 through 45. Although periodic nourishment is considered continuing construction, interest during construction is only calculated on PED expenditures through the time that a project element starts to function. Therefore, there would be no IDC for the nourishment cycles. The district should revise the analysis of IDC in the draft report to show IDC for initial construction only.

District Response: Concur, this will be re-evaluated and updated in the draft report.

Discussion: Concern is resolved.

Action: The draft report will include the revised analysis of interest during construction.

c. Clean Up Costs: Table 5.2 indicates that public cleanup costs would be completely eliminated by the recommended plan despite the fact that there are residual damages from wave attack and inundation. This seems counterintuitive since clean up costs are generally experienced throughout the range of storm events. The district should review the assumptions for the estimates of cleanup costs to assure that the appropriate level of benefits and residual damages are being used to identify the NED plan.

District Response: Concur, this will be re-evaluated and updated in the draft report

Discussion: The district will also review to ensure consistency with earlier concern on residual damages.

Action: The district will review and update the numbers in the report as appropriate.

d. OMRR&R Cost: The AFB document does not address non-Federal OMRR&R costs. Typically, activities such as maintenance of dune vegetation and walkover structures, and emergency shaping of the beach to correct localized accumulation or depletion of sand after storms are considered non-Federal O&M responsibilities. Non-Federal OMRR&R requirement should be identified in the draft report and included in the economic evaluation of project alternatives.

District Response: The project area does not consist of dunes or walkover structures. No emergency shaping of the beach is required for the NED plan. There are no O&M requirements associated with the NED plan.

Discussion: Monitoring and clean up costs are minimum activities for project maintenance. In the case for monitoring for renourishment, this activity is cost-shared between Federal and non-Federal interests. Monitoring for other purposes is financed completely by the non-Federal sponsor. The draft report should discuss OMRR&R requirements of the project.

Action: The district will identify any potential operation and maintenance cost associated with constructed project. The report should note that Corps hurricane and storm damage reduction projects require, as an item of local cooperation, that non-Federal sponsors maintain the design profile. Typically, this is accomplished by moving sand displaced by storms from one segment of the project and deposited in another project segment. The report should address whether this requirement can be satisfied given California Coastal Commission regulations. Note that if this requirement cannot be satisfied, there may be implications as to the validity of the assumption that the design profile will be available to prevent damages for the full period of economic evaluation.

7. :

a. Draft EIS: The draft EIS is still incomplete, awaiting more information, either from the Corps study team or from other agencies. This missing information should be provided to HQUSACE for review prior to finalization of the draft EIS.

District Response: Concur. The document contained in this AFB Report is a preliminary draft. Missing information shall be provided in the Draft EIS and submitted to HQUSACE for review prior to public distribution.

Discussion: Concern is resolved.

Action: The Draft EIS will be submitted to HQUSACE for review prior to public distribution.

b. Draft EIS-NEPA Requirements: Paragraphs 11 and 12 of the draft EIS (Relationship between short-term Uses of the Environment and Maintenance and Enhancement of long-term Productivity; Irreversible and Irretrievable Commitment of Resources) are, as presently written, merely discussions of what the State and Federal laws require. They do not discuss specifics of the proposed alternatives and how they relate to the required analyses. At present, these paragraphs are totally inadequate.

District Response: Concur. Since this report is the preliminary alternatives analysis, a discussion of specifics of the proposed alternatives and how they relate to the required analysis was postponed since the alternatives and recommended alternative changed several times, including after the F4 document was submitted. The required discussion will be included in the Final Draft EIS and submitted to HQUSACE for review prior to public distribution.

Discussion: Concern is resolved.

Action: As indicated in the response.

c. Endangered Species: There may be an opportunity to provide least tern nesting areas in conjunction with the project that are separated from public intrusion and other forms of nest destruction or harassment of young birds while still on the nest. The district should examine all potential for restoration of such uses of the restored beach by species of special concern.

District Response: The proposed project is sited adjacent to an existing U.S. Fish & Wildlife Service designated “Least Tern Nesting Area”. The project, as proposed will provide protection to the existing nesting area by placing a sand berm barrier in close proximity to this site, thereby separating the existing nesting area from public intrusion and other forms of nest destruction or harassment. However, additional opportunities to provide nesting areas for species of special concern may be investigated.

Discussion: Concern is resolved.

Action: The draft EIS will include information in the response. The district will not investigate additional environmental opportunities.

d. Required Mitigation Measures: The Environmental Appendix indicates that a number of mitigation measures are proposed for the recommended plan. No significant adverse impacts are identified and attributed to construction of the recommended plan. Consequently, there appears to be no mitigation requirement. The measures discussed in the Environmental Appendix are ways of avoiding impacts through sound planning of the project--not mitigation. This should be clarified in the report.

District Response: Concur. No significant adverse impacts are attributed to construction of the recommended plan as described. The final Draft EIS will clarify that any environmental commitments to minimize short-term construction-related impacts are not considered to be mitigation measures and no mitigation is required.

Discussion: Concern is resolved.

Action: As indicated in the response.

8. LOCAL COOPERATION: Page 6-2 contains a list of non-Federal responsibilities, which is abbreviated and omits several items of local cooperation typically required for shore protection projects. A complete and accurate list is required by ER 1105-2-100 app. G-9.g.(1)(d). Office of Chief Counsel, HQUSACE, offers the following draft list for hurricane and storm damage reduction projects. The District should review the list carefully, with the assistance of its Office of Counsel, and revise it further as needed to address the needs of the current project.

District Response: Concur. The data contained in Chapter 6 is in error. The report will be revised to include the correct cost sharing apportionment. The District will review the following draft list provided by the HQUSACE Review Team with Office of Counsel and revise as needed to address the needs of the current project.

Discussion: As indicated in the response. Also see comment

Action: As indicated in the response.

9. REAL ESTATE: The AFB document does not contain any real estate information for policy review. The draft report should include a real estate plan that satisfies the requirements of ER 405-1-12. The real estate appendix should also address public access and other requirements that are unique to hurricane and storm damage reduction projects.

District Response: Concur. Real estate appendix will be included in the draft report. In general, the mining, transport and placement of beach nourishment material will take place entirely on public lands or in public waters. Local and state ordinances will ensure public accessibility to the constructed project site. Beach nourishment material will be mined from offshore sources within the jurisdictional waters of the State of California. Typically fees are not assessed on the excavation of offshore sediments for the purpose of providing beach fill on public lands.

Discussion: The information contained in the response will be included the draft real estate plan included in the draft report.

Action: The draft real estate plan will be included in the draft report.

10. MISCELLANEOUS:

a. Outdated Explanation of Review and Approval Process: Much of the material contained in paragraph 6.7 is out of date. For instance, there is no longer a requirement for a 90-day state and agency review (paragraph 6.7.c). This review is now 30 days. Refer to ER 1105-2-100, Appendix H for current information.

District Response: Concur. The data contained in Chapter 6 is in error. The report will be revised to include the current review and approval process.

Discussion: Concern is resolved.

Action: The district will remove Chapter 6 in its current form and replace it with updated requirements.

b. Imprecise Text: The report indicates that the Federal Government and the non-Federal sponsor are responsible for implementing and maintaining the project. Actually, the Federal Government and non-Federal sponsor are responsible for initial construction and periodic nourishment of the project. The non-Federal sponsor is responsible for operation and maintenance of the project to include maintaining the design profile.

District Response: Concur. The draft report will be revised to correct this imprecise text.

Discussion: Concern is resolved.

Action: The district will revise the text in the draft report.

c. Misleading Text: The report indicates that typically property owners do not heed warnings nor properly prepare prior to storm events and as a result sustain damage to structure contents as well as loss of actual structures. This implies that property owners could have avoided content damages with proper preparation. This appears to be misleading statement, as evacuation does not typically include removing all contents from structures. Suggest more appropriate wording be used.

District Response: Concur. The district will revise misleading text. This section will be re-visited along with the content to structure ratios discussed in paragraph 4.

Discussion: Concern is resolved.

Action: The district will revise the text in the draft report.

d. Typographical Error: The summary of without project damages (Table 3.8) has total without project damages to include recreation transfer costs of $2,309,000. This amount should be $2,054,000.

District Response: Concur. The draft report will be corrected to include the correct recreation transfer costs.

Discussion: Concern is resolved.

Action: Text will be corrected in the draft report.

CECW-PM 4 March 2002

COASTAL STORM DAMAGE ASSESSMENT MODEL

INPUTS