Site Conditions
Sybil Creek is a tidally dominated marsh system located within the Branford River watershed in Branford, Connecticut. The marsh system (Fig. 1) consists of two major habitats; those below the tide gates (West Marsh) supporting a healthy New England type marsh dominated by salt marsh grasses (Spartina spp.) and the areas located above the gates on Rt 146 (East, Central and North Marshes) that supports large stands of common reedgrass. The hydrology of the area above Rt 146 has been restricted for the better part of this century and the changes in habitat structure are common to many New England tidal marshes where similar restrictions to the tides have been observed. The Sybil Creek site was first identified during the early 1980's as a site of importance for restoration (Orson et al., 1982). Problems with homes built at or below sea level has delayed restoration of the site until now. At present, engineering plans and finances are in place so that the restoration of the site can begin to move forward. Within the next few years, the State of Connecticut will increase tidal flushing to the site and begin a program of restoration using hydrologic manipulations. Before that project begins it will be imperative that baseline sampling be conducted at the site prior to restoration so that it will be possible to establish and assess the success of any management plan for the area (Orson et al., 1997).

An engineering analysis completed in 1996 (Milone and MacBroom 1996) divided the Sybil Creek marsh system into four major areas; the East Marsh (areas downstream of Rt 146), Central Marsh (marsh just above the gates at Rt 146 at the end of Waverly Rd, North Marsh (the extension of Central Marsh beyond a major upland island and upstream of Waverly Park Rd) and West Marsh (marsh above the Waverly Park Rd culvert that runs out along the coast). For purposes of discussion here we will use the same divisions in this report (Fig. 1).

The 1996 engineering report found that the channel invert elevations at the tide gates on Rt 146 were -2.95 ft. (-0.90 m) NGVD downstream and -0.65 ft (0.20 m) NGVD upstream with the typical marsh elevation in the restricted marsh at 1.2 (0.37 m) to 1.4 ft. (0.43 m) NGVD. It was also noted that the occurrence of high tide upstream of the gates (Central marsh channel) lagged behind the unrestricted marsh by about 2 hours. Under normal tides, the highest measured water elevations were 4.9 ft (1.49 m) NGVD below Rt 146 and 0.9 ft (0.27 m) NGVD above Rt 146. However during a storm event (nor'easter), highs were recorded at 6.27 ft. (1.91 m) NGVD and 1.46 ft. (0.44 m) NGVD three hours later, respectively.

While investigating the hydrology and topography of the site, the 1996 report also collected some salinity and pH data (Table 1). The analyses showed that the salinities below the gates are similar to those found in the harbor and along the coast (between 20 and 25 ppt) while those measurements taken above the Rt 146 gates were considerably lower. Similar trends were noted during this investigation (Table 1). Acidification of the system was not a problem (the lowest measured pH was 6.5 in the East Marsh).

TABLE 1. Water salinity readings for Sybil Creek. 1995 Salinity and pH readings taken on November 28, 1995, during a flood tide (from Milone and MacBroom 1996). 2000 Salinity readings were taken on August 16, 2000 during a flood tide [note: summer 2000 was wet and cool]

LOCATION	Salinity (ppt) 1995/2000	Depth (m)	pH	Water Surface Elevation (m) NGVD
-
WEST MARSH	-	-	-	-
D/S Rt 146	10/17	surface	7.58	0.88
-	8/18	surface	-	-
-	20/21	0.61	-	-
-	20/21	1.22	-	-
-	21/21	1.52	-	-
Transect #1	x /21	0.30	-	-
Transect #2	x /19	0.30	-	-
	-	-	-	-
CENTRAL MARSH	-	-	-	-
U/S Rt 146	20/18	surface	7.49	0.19
-	20/19	0.46	-	-
-	21/19	surface	-	0.26
End of Waverly Rd	14/16	surface	7.39	-
D/S Waverly Park Rd	7/9	surface	-	-
-	19/ x	surface	7.66	0.15
Transect #3	x /11	0.30	-	0.16
	--	-	-	-
NORTH MARSH	-	-	-	-
ditch	3/ x	surface	7.64	0.16
main channel	x /9	0.30	-	-
Transect #4	x /7	0.30	-	-
Transect #5	x /5	0.30	-	-
-	-	0.30	-	-
EAST MARSH	-	-	-	-
U/S Waverly Park Rd	7/8	surface	-	-
near condos	5/6	surface	6.50	-
panne	10/3	surface	-	-
panne	5/3	surface	-	-
panne	10/7	surface	-	-
channel	x /6	0.30	-	-

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