III. Freshwater Canals A. Introduction Broward County’s current system of drainage consists of approximately two hundred and sixty-six miles of waterways (Broward County Planning Council 1989). The primary drainage system is managed by the South Florida Water Management District (SFWMD) and consists of nine major canals and their corresponding drainage basins (Figure III.1): Hillsboro Canal, C-14 (Cypress Creek) Canal, Pompano Canal, C-13 (Middle River) Canal, C-12 (Plantation) Canal, North New River Canal, C-11 (South New River) Canal, C-9 (Snake Creek) Canal, and the C-10 (Hollywood) Canal. These nine major canals, along with secondary and tertiary canals, eventually drain to the main estuarine areas (i.e., Intracoastal Waterway; see Section IV). The exception is the western segment of the C-11 Canal which is normally backpumped into the Water Conservation Area (WCAs). Overall, the canals are primarily used for flood control, however, secondary uses include drainage of land for development, discharge of excess water to and from the WCAs, prevention of saltwater intrusion, and recharge of wellfields (Cooper and Lane 1987). The result is a highly managed, intricate system of canals and retention ponds with control structures and pumps that maintain the balance between flood prevention and over drainage. The chemical characteristics of canals must be studied in order to understand possible ‘downstream effects’ on receiving water bodies (i.e., the Everglades and coastal systems). While the canal system’s primary function has been and continues to be conveyance, the waterways are currently considered waters of the state of Florida also known as Class III waters (see Florida Administrative Code [FAC] 62-302; State of Florida 1998). Class III waters are designated as being used for “recreation, propagation and maintenance of a healthy, well-balanced population of fish and wildlife” (FAC 62-302.400). Despite habitat limitations, aquatic populations exist within the canals but the abundance and diversity of these organisms has rarely been quantified in Broward’s urban waterways (but see Florida Game and Freshwater Fish Commission 1985). The canals are used by a relatively large group of recreational fishers. Largemouth bass, Micropterus salmoides, is a popular species of choice, as well as the recently introduced peacock bass, Cichla ocellaris, which has thrived in Miami-Dade and Broward Counties (http://www.state.fl.us/ gfc/fishing/Fishes). Thus, these waterways are being used in ways that differ from their primary function of drainage but are consistent to some extent with their regulatory classification. Understanding the chemistry of these canals is important in determining the water bodies’ potential to support biological populations. B. Objectives and Scope Four major objectives constitute the framework for the study and include: i Determine water quality conditions (long-term and current) at each freshwater canal sampling site; i Determine compliance patterns with Broward County’s Chapter 27 water quality standards (Broward County 2000); 14 i Determine similarities and differences existing within each basin or region; and i Formulate research questions, needs, and direction for better management of the entire Broward freshwater canal system. At the core of this freshwater canal investigation is a three-part data analysis performed at each sampling site in a particular basin. < An initial descriptive statistical analysis of all parameters and data collection years for each site; < Graphical analyses of major parameters (dissolved oxygen, total phosphorus, total nitrogen, and fecal coliform) at each site; and < Graphical and statistical analyses of major parameters collected during post- wastewater treatment plant discharge years with a focus on seasonal concentrations. The descriptive analysis provides a historic snapshot of the total sampling effort at each particular site. Graphical analysis was performed to investigate inter- and intra- annual variation. Furthermore, graphical analyses was performed to better understand the influence of wastewater treatment plant (WWTP) discharges to surface waters to both the observed concentrations and water quality standard compliance. Finally, an attempt to discern seasonal differences was performed graphically and statistically for the years 1989 through 1997. This also allowed for better interpretation of overall water quality post-WWTPs, as well as integrating known dry, wet, and average rainfall years similar to modeling efforts of the Water Preserve Areas (WPA) Feasibility Study (http://www.evergladesplan.org /projects/wpa_main.htm). The WPA study is looking at the possibility of storing water in the western portions of developed south Florida for better management of water supply to Everglades Restoration and public water supplies. C. Freshwater Regions A majority of the nine drainage basins have freshwater canals that discharge eastward to estuarine sections through coastal salinity control structures depending on water elevations (Figure III.1). Estuaries are semi-enclosed water bodies with a free connection to the sea and a defined freshwater source (Comp and Seaman 1985). Some stretches of a similarly named water body may be considered the headwaters and the tailwaters of a control structure (Table III.1). Perhaps more importantly, certain canals (e.g., Hillsboro) have both freshwater and estuarine segments. The C-10 Canal is actually all within an estuarine system and will be discussed in Section IV. For this section, the freshwater segments are the primary focus with the exception of one C-13 Canal location (Site 11) which is immediately east of the control structure S-36 (Figure III.1). 16 c) .--v > l-- a ts 6,:*_ cd oo rr) - U d av --9 z a 6- e o a !v -? A) O z (J z C) uzzt) U O O}: i-l a4 a 'a Z 9 =9.- (, 0,) d'! rllo og zx AE {i cr z= =: ! 2,4 +B @cd xo 62. ,YZ,^ vc6 a --. iz 8> E6; C)9 :C) t-. +f F- f -Y o>' : o'=> $i =z =r>- )>J- B v ,^ :> (n \) -7t:^/v^ | , r= (, O3 a U 29 3'p,49 6B a c) .- oq) trl F 6S c,) J} N z Us C€ rrl rll $ o] Tq 92 'E ?3 r) *'' ai co3 :EO UO O U zg 2C ::: q.) 6.) t9 o a cg C! 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Cir +i F- 9>. ci 0) rr l YV za rl.] C, ,: o. _E u)v <+ o U rl Z a) 0.)A 6.1 ';e c9 'Cl P -(H a) liF Ptr b I,t tr> = a ;= C6 U U fi- < --1Ii U ald. I I )u- U U z U v(J ,': v ra .F I! r ) -G) 3 * *? * UF -a * o * <d 'ua : N z' A) a z 0 Je .te l8 From Table III.1, the freshwater canal regions of the county can be broken down into the following eight major canals from north to south- Hillsboro, C-14, Pompano, C-13, C-12, North New River, C-11, and C-9. A long term data set does not exist for the Pompano Canal, thus, seven freshwater regions will be addressed in this report. The Pompano Canal Basin, located in northeastern Broward, is the smallest in the county with an area of just over seven miles square (mi2, Cooper and Lane 1987). However, BCDPEP began monitoring the Pompano Canal at Dixie Highway in 1999, in part, to better understand the water quality of discharges to estuarine waters. Future reports will detail water characteristics of this basin. D. General Hydrological Characteristics Water management by the SFWMD, Broward County Office of Environmental Services (BCOES) and/or Independent Drainage Districts is often determined by rainfall, water elevations, and/or threat of tropical storms and hurricanes. Thus, flow volume and rate can be quite variable within the same canal system, as well as between adjacent canals. In essence, Broward’s waterways represent a large, complex “outdoor plumbing” system designed to provide flood protection and drinking water aquifer recharge and to maintain groundwater elevations. Basin specific hydrological information primarily derived from Cooper and Lane (1987) will be presented with each of the seven canals. Groundwater can also be an important inflow to the South Florida freshwater canals due primarily to the transmissive nature of the Biscayne Aquifer (Lietz 1999). Groundwater interaction with the canals is highly dependent on rainfall, tidal flow, and consumptive use patterns by the local population.