Updated  10/13/06

Progress Report

Tasks I through III

Phase I Long Range Dredged Material Management Plan

for the Intracoastal Waterway

in Broward County

 May 4, 2000

This report summarizes the results of our work on Tasks I through III for the Phase I development of the Long Range Dredged Material Management Plan for the Intracoastal Waterway (ICWW) in Broward County, Florida (Figure 1). Specific efforts expended in the completion of these tasks, as well as results obtained from these efforts, will be reported to the project’s Citizens’ Advisory Committee and the general public on May 4th, the project’s Technical Advisory Committee on May 24th, and the FIND Board of Commissioners on June 23rd at their regularly scheduled meeting in Brevard County.

The attached tables and figures [in preparation] summarize the results of Tasks I through III.  Task I results reflect the analysis of information from materials collected during project Task I-A (data collection). These materials include U. S. Geological Survey (USGS) NAPP 1994 color-infrared aerials, USGS 7.5-minute series topographic quadrangle maps, and U. S. Fish and Wildlife Service National Wetland Inventory maps (all at a scale of 1:24,000) of the entire project area, 1994 Florida Inland Navigation District (FIND) blueline aerials of the Waterway, existing disposal easements and FIND-owned properties (1:2,400), Jacksonville District Corps of Engineers Real Estate and Control Data maps, 1999 Broward County Tax Assessment aerials (scale 1:3,600), and Broward County Comprehensive Plan future land use elements and maps. As part of this task, we have reviewed all relevant dredging records (plan documents, surveys, dredging summaries, OCE  reports, etc.) held by the Jacksonville District Corps of Engineers (COE). We also have analyzed the comprehensive survey data from the FIND’s 1996 survey of the entire ICWW channel. We have just recently (April 21st) received data from the Jacksonville District’s recent survey of the entire ICWW channel and are now beginning to analyze this data. Finally, we have reviewed all available sediment data and reports from the Florida Department of Environmental Protection and South Florida Water Management District characterizing the chemistry of the Waterway sediments. However, we still await Jacksonville District COE core boring, grain-size distribution, and sediment chemistry data, presently being obtained and processed, before we determine the most appropriate channel locations in which to concentrate our planned sediment sampling, not yet scheduled.

The Broward County segment of the ICWW area extends 25.0 miles from its starting point approximately 650 ft south of the Palm Beach\Broward County line (ICWW mile 309.24; Cut BW-1, Station 0+00) to its endpoint approximately 530 ft south of the Broward\Dade County line (ICWW mile 333.24; Cut DA-1, Station 0+00 (Figure 1). The county’s northernmost 650 ft lie within Cut PB-91 and are addressed as part of the long-range plan for the ICWW in Palm Beach County. To provide a project framework, Table 1 lists all of the Broward County channel cuts (i.e., the straight line channel segments), cut lengths, and mileages measured from the northern boundary of the Broward County project area, as well as from the St. Johns River in Jacksonville (specifically, the southern edge of the Jacksonville Harbor Project, designated ICWW mile 0.0).

To project future dredging and material storage requirements for the Broward County project area, we first compiled and reviewed all available Jacksonville District, U.S. Army Corps of Engineers’ (COE) archival dredging records and channel surveys, as stated above. By this process, we determined that no maintenance dredging has been performed in the Broward County segment of the ICWW since the 1965 deepening of the channel to its presently authorized depth of -10 ft Mean Low Water (MLW). Thus, the shoals documented in the FIND’s December 1996 three line survey of the entire ICWW, including the Broward County segment, represent all historic shoaling within the Broward County project area since the establishment of the present project depth (Figure 2).  As shown in Table 2, these shoals represent a total in situ volume of 32,245 cubic yards (cy). From these data, we then projected a 50-year material storage requirement of 108,323 cy, based on an assumed bulking plus overdredging factor of 2.15. This volume represents the smallest 50-year material storage requirement of any of the 12 coastal counties that comprise the FIND. Notably, almost 95% of this projected requirement reflects shoaling within the project area’s northernmost 7.4 miles in an area centered about Hillsborough Inlet, located opposite ICWW mile 313.3. Although sufficient to guide our initial identification and evaluation of candidate sites, this projected material storage requirement will be refined based on the results of the Jacksonville District’s recently completed three line survey of the entire ICWW, including the Broward County segment.

We also inventoried all existing disposal easements and FIND-owned properties within the Broward County project area, based on review of relevant COE Real Estate maps and Control Data sheets for the Intracoastal Waterway, Jacksonville to Miami, and 1994 FIND blueline aerials. We then derived preliminary estimates of site parameters (e.g., upland acreage, capacity, pipeline access, etc.) from the above described resource materials.  A complete inventory of all existing easements and FIND-owned properties and the results of the preliminary easement evaluation process are summarized in Table 3 and Figure 3. By this process, we determined that five existing sites, comprising seven individual easements or FIND-owned properties, possess realistic potential for development as dredged material management areas and thus merit further evaluation. The estimated total storage capacity of these five sites, estimated as over 151,000 cy, exceeds the projected 50-year storage requirement of the Broward County project area. However, use of these sites may not represent the most cost-effective or operationally efficient means of meeting these long-term needs of the Waterway within Broward County. Moreover, four of the five existing sites, representing almost 95% of the existing capacity, fall within the project area’s northernmost 5.5 miles. We are now refining these preliminary estimates of useable site acreage and potential site capacity within these seven sites based on field inspections and detailed site mapping as discussed below.

Based on the results of Task I and review of the overall physical, environmental, and demographic characteristics of the coastal areas of the county, we then preliminarily identified the most appropriate material management strategy for the requirements of the Broward County project area. Given the concentration of shoaling around Hillsborough Inlet, and the likely presence of beach-quality channel sediments in this segment of the Waterway, beach placement, supplemented by an nearby upland staging and material transfer area, appears to be the most appropriate management strategy for this channel segment. However, the presence of beach-quality channel sediment must be demonstrated by sediment data soon to be to be received from the Jacksonville District COE, and confirmed by additional sediment sampling based on this data. For all other areas of the Broward County project area, the use of confined upland placement in a limited number of centralized material management areas appears the most appropriate material management strategy. Based on these preliminary management concepts, we then delineated three operational channel reaches. Table 4, and Figure 4 present the preliminary delineation of these channel reaches, discussed below.

Reach I (Figure 5), the northernmost reach, extends from a point 650 ft south of the Palm Beach/Broward County line (ICWW mile 309.24; Cut BW-1, station 0+00), southward 9.28 miles to the E. Commercial Blvd (State Road 870) Bridge (ICWW mile 318.52; Cut BW-27, Station 26+00). The projected 50-year material storage requirement for this reach, 102,762 cy, represents almost 95% of the projected requirement for the entire Broward County project area (Table 5).  Four of the five existing sites that demonstrate some potential for continued use fall within this reach.  As stated above, we anticipate that channel sediments within this reach to be predominantly clean, fine to medium quartz sand suitable for beach placement.

Reach II extends southward 7.13 miles from the end of Reach I to a point 1,350 ft south of the Seabreeze Blvd. (S.R. A1A) Bridge immediately north of Port Everglades (ICWW mile 325.65; Cut BW-50, station 0+00).  The projected 50-year material storage requirement for this reach, 4,807 cy, represents less than 5% of the total requirement for the Broward County project area.  None of the existing sites demonstrating some potential for continued use fall within this reach.

Reach III extends from the southern end of Reach II southward 8.59 miles to a point 530 ft south of the Broward/Dade County line (ICWW mile 333.24; Cut DA-1, station 0+00), approximately 0.89 miles south of the E. Hallandale Blvd. (S.R. 858) Bridge.  The projected 50-year material storage requirement for this reach, less than 1,000 cy, suggests the likely requirement of only a minimal dredged material management site.  Only one of the five existing sites preliminarily determined to have some potential for development as dredged material management sites, MSA 784 (estimated capacity, less than 10,000 cy), falls within this reach.

Although not yet final, the results of Task I, the preliminary definition of appropriate management concepts, and the preliminary delineation of operational channel reaches then guided the identification of 54 additional candidate sites based on an office review of 1994 NAPP color-IR aerial photography, USGS 7.5-minute topographic quadrangle maps, Comprehensive Plan Future Land Use maps and U.S. Department of the Interior wetland inventory maps. To update each candidate site’s present land use, we then obtained current (1999) Broward County tax aerials for each area identified. Through review of these aerials, we eliminated 13 candidate sites with obvious land use conflicts (i.e., recent development) not shown in the 1994 aerials, and thereby reduced the number of required candidate site inspections. Field inspection of the remaining candidate sites (Figure 6 and Table 6), as well as the five existing sites that show some potential for development as dredged material management areas, was conducted the weeks of April 10th and April 24th. A team consisting of one engineer and one biologist inspected each existing and newly- identified candidate sites not presently available to the FIND to determine existing land uses on and adjacent to each site, to characterize and preliminarily quantify on-site vegetation communities and associated environmental liabilities, and to assess the general suitability of each site for development as permanent dredged material management facilities.

In Task IV, each candidate site will be further evaluated under the full standard set of engineering, operational, environmental, socioeconomic, and land-use criteria. We are now mapping land use and vegetation communities on each site to Level 3 of the Florida Land-Use and Cover and Forms Classification System (FLUCS) (FDOT, 1985), based on the 1999 Broward County aerials. When completed, these maps will guide a refined estimate of each site’s dredged material storage capacity, based on realistic containment basin geometries, field-verified environmental constraints, and appropriate setback considerations.  The resulting site capacities, acreage requirements, and basin geometries, as well as each site’s associated reach requirements and land-use parameters, will be outlined in a Site Data Summary Sheet to accompanying each candidate site map.

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