Lake Worth Lagoon Waterways Town of Palm Beach, Florida North Waterway

Transcription

1 North Waterway STATE OF FLORIDA PROJECT AREA N R-100 R-101 R-102 R-103 R-104 R-105 R-106 R-107 R-108 R-109 R-0 R-1 T-2 R-3 R-4 R-5 R-6 R-7 R-8 North Waterway Central Waterway South Waterway Dredge Hole NTS PROJECT AREA 3,100' +/- 561) Location Map North Waterway Sheet: 1 of 5 Job Number: Issue Date:

2 2.51' MLW 2.22' MLW 0.29' NAVD ' NAVD yan Rd PROPOSED 30' SECONDARY CHANNEL TYP) N-3b Via Del Mar 210 Via Del Mar Via Vizcaya Via Vizcaya 12 Via Vizcaya SEGMENT N3 1450' +/- 10 Via Vizcaya Vita Serena Clarendon Ave. 261 Via Bellaria Via Bellaria 0.00' MLW -2.22' NAVD88 TIDE DATUM Via Del Lago 212 Via Palm SEGMENT N2 415' +/- N-4b N ' +/- SEGMENT N2 N-2b NO SEAGRASS OBSERVED DURING JUNE 2014 SURVEY. GRAB SAMPLE LOCATIONS TYP) SECONDARY CHANNEL TYP) N-7 SEGMENT N4 839' +/- SEP SURVEY CONTOUR LINES TYP) NORTH MAIN Segment Length ft) Volume cy) N N N N SEGMENT N1 1275' +/- N-1b PROPOSED 40' WIDE MAIN N-9b INTRACOASTAL N-8 Cut Thickness Minimum Maximum Thickness Thickness 6.0' Total Color NORTH Main Channel Segment Secondary Cut Volume cy) N2 825 N3 804 N4 90 Total 1719 NOTE: BATHYMETRIC SURVEY PERFORMED BY APPLIED TECHNOLOGY AND MANAGEMENT; DATED SEPTEMBER BATHYMETRIC SURVEY RELATIVE TO NAD83 FLORIDA STATE PLANE, EAST ZONE, US FEET, VERTICAL DATUM NAVD88. AERIAL PHOTOGRAPHY DATED JULY ' 561) North Waterway - Plan View North Waterway Sheet: 2 of 5 Job Number: Issue Date:

3 2.51' MLW 2.22' MLW 0.29' NAVD ' NAVD88 ia Vizcaya aya 10 Via Vizcaya Vita Serena Clarendon Ave. 261 Via Bellaria Via Bellaria Via Del Lago Algoma Rd. Via Palma 165 Kings Rd. 176 Kings Rd. 185 Woodbridge Rd. 0.00' MLW -2.22' NAVD88 TIDE DATUM 00 Reg 70 N ' +/- 480 ' +/- Channel Extension N-7 NO SEAGRASS OBSERVED DURING JUNE 2014 SURVEY. PERMIT MODIFICATION CHANNEL ADDITION AREA. NORTH MAIN Segment Length ft) Volume cy) 80' Wide Turning Basin DETAIL N N N N N-8 INTRACOASTAL 100' 80' BRIDGE Cut Thickness Minimum Maximum Thickness Thickness Total Color NORTH Main Channel Segment Secondary Cut Volume cy) N2 442 N3 425 N4 3 Total 870 NOTE: BATHYMETRIC SURVEY PERFORMED BY APPLIED TECHNOLOGY AND MANAGEMENT; DATED SEPTEMBER BATHYMETRIC SURVEY RELATIVE TO NAD83 FLORIDA STATE PLANE, EAST ZONE, US FEET, VERTICAL DATUM NAVD88. AERIAL PHOTOGRAPHY DATED JULY ' N APPLIED TE CHNOL OGY& MA NA GE MENT 561) SM North Waterway - Plan View Channel Extension North Waterway

4 478' +/- NOTE: 1. BATHYMETRIC SURVEY PERFORMED BY APPLIED TECHNOLOGY AND MANAGEMENT; DATED SEPTEMBER BATHYMETRIC SURVEY RELATIVE TO NAD83 FLORIDA STATE PLANE, EAST ZONE, US FEET 2. AERIAL PHOTOGRAPHY DATED JULY ' MLW 2.22' MLW 0.29' NAVD ' NAVD Regents Park Rd PERMIT MODIFICATION CHANNEL ADDITION AREA 400 Regents Park Rd Regents Park Rd ' 213' +/- 0.00' MLW -2.22' NAVD88 TIDE DATUM 52' +/- 197' +/- 54' 865' +/- 1473' +/- PROPOSED 30' SECONDARY SECTION CUT A PROPOSED 30' SECONDARY CHANNEL TYP) PROPOSED 30' SECONDARY SECTION CUT B S-8b SEP SURVEY CONTOUR LINES TYP) CENTRAL MAIN Segment Length ft) Volume cy) C Total NO SEAGRASS OBSERVED DURING JUNE 2014 SURVEY. PROPOSED 40' WIDE MAIN GRAB SAMPLE LOCATIONS TYP) S-9b SEGMENT ' +/- CENTRAL Secondary Cut Main Channel Segment Volume cy) C Total 6070 Cut Thickness Minimum Maximum Color Thickness Thickness 0.0' S-10b N INTRACOASTAL APPLIED TE CHNOL OGY& MA NA GE MENT 561) SM Central Waterway - Plan View Central Waterway Sheet: 2 of 7 Job Number: Issue Date:

5 NOTE: 1. BATHYMETRIC SURVEY PERFORMED BY APPLIED TECHNOLOGY AND MANAGEMENT; DATED SEPTEMBER BATHYMETRIC SURVEY RELATIVE TO NAD83 FLORIDA STATE PLANE, EAST ZONE, US FEET 2. AERIAL PHOTOGRAPHY DATED JULY SEAGRASS SURVEY CONDUCTED JUNE 12 & 13, MATCHLINE 7 Lagomar Rd Lagomar Rd Lagomar ` 4 Lagomar Rd Rd. S-5b 1600 ` Seagrape Circle PROPSED 30' SECONDARY CHANNEL TYP) ` 126 Seagrape Circle Via Fontana Parc Monceau 125 Parc Monceau 124 Parc Monceau S-4b 1768 GRAB SAMPLE LOCATIONS TYP) SEAGRASS FOUND IN THIS AREA 0.007ac) REFER TO FIGURE 4 SEGMENT S1 00' +/- SEP SURVEY CONTOUR LINES TYP) PROPOSED 40' WIDE MAIN SEGMENT S2 1880' +/- SOUTH Secondary Cut Main Channel Segment Volume cy) S S S S Total 8927 Cut Thickness Minimum Maximum Thickness Thickness 6.0' 0.0' Color SOUTH MAIN Segment Length ft) Volume cy) S S S S S Total INTRACOASTAL NOTE: 1. BATHYMETRIC SURVEY PERFORMED BY APPLIED TECHNOLOGY AND MANAGEMENT; DATED SEPTEMBER BATHYMETRIC SURVEY RELATIVE TO NAD83 FLORIDA STATE PLANE, EAST ZONE, US FEET 2. AERIAL PHOTOGRAPHY DATED JULY SEAGRASS SURVEY CONDUCTED JUNE 12 & 13, ) South Waterway - Plan View South Waterway Sheet: 2 of 7 Job Number: Issue Date:

6 MATCHLINE NOTE: 1. BATHYMETRIC SURVEY PERFORMED BY APPLIED TECHNOLOGY AND MANAGEMENT; DATED SEPTEMBER BATHYMETRIC SURVEY RELATIVE TO NAD83 FLORIDA STATE PLANE, EAST ZONE, US FEET 2. AERIAL PHOTOGRAPHY DATED JULY SEAGRASS SURVEY CONDUCTED JUNE 12 & 13, SEGMENT S3 500' +/ SEP SURVEY CONTOUR LINES TYP) PROPSED 30' SECONDARY CHANNEL TYP) S-3b SEGMENT S2 1880' +/- S-2b SEGMENT S4 1620' +/- SOUTH MAIN Segment Length ft) Volume cy) S Cut Thickness Minimum Maximum Thickness Thickness 6.0' Color PROPOSED 40' WIDE MAIN 1445' +/- SEGMENT S5 GRAB SAMPLE LOCATIONS TYP) S S S S Total SOUTH Secondary Cut Main Channel Segment Volume cy) 0.0' S-1b S S S S Total 8927 INTRACOASTAL DREDGE HOLE SITE 561) South Waterway - Plan View South Waterway Sheet: 3 of 7 Job Number: Issue Date:

7 2.51' MLW 2.22' MLW 0.29' NAVD ' NAVD88 ia Vizcaya aya 10 Via Vizcaya Vita Serena Clarendon Ave. 261 Via Bellaria Via Bellaria Via Del Lago Algoma Rd. Via Palma 165 Kings Rd. 176 Kings Rd. 185 Woodbridge Rd. 0.00' MLW -2.22' NAVD88 TIDE DATUM 00 Reg N ' +/ Channel Extension 480 ' +/ N-7 NO SEAGRASS OBSERVED DURING JUNE 2014 SURVEY. PERMIT MODIFICATION CHANNEL ADDITION AREA. 80' Wide Turning Basin DETAIL BRIDGE N-8 80' NORTH MAIN Segment Length ft) Volume cy) 100' Extension INTRACOASTAL NOTE: BATHYMETRIC SURVEY PERFORMED BY APPLIED TECHNOLOGY AND MANAGEMENT; DATED SEPTEMBER BATHYMETRIC SURVEY RELATIVE TO NAD83 FLORIDA STATE PLANE, EAST ZONE, US FEET, VERTICAL DATUM NAVD88. AERIAL PHOTOGRAPHY DATED JULY N APPLIED TE CHNOL OGY& MA NA GE MENT 561) SM North Waterway - Plan View Channel Extension North Waterway

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9 The proposed Mar-A-Lago channel was inspected on March 30, A marine scientist on snorkel swam a transect through the centerline of the dredge area; water depths were between 4 and 6 ft. during the inspection. No seagrass was observed, and the substrate was silty sand with shell hash. Water depths during the inspection were deeper than the mean depths at which seagrass was found in the central segment of the lagoon during the 2013 Lake Worth Lagoon Mapping Project CEG, 2014). The lower water clarity in the central segment of the lagoon has resulted in a retreat of seagrass to shallower depths in recent years. During the 2013 mapping project, the central segment was the only segment with a mean Secchi depth of less than 1.0 m. The mean depth of all sites where seagrass was present was -3.5 ft NAVD while the mean depth of sites where seagrass was absent was substantially deeper at -5.3 ft NAVD CEG, 2014). Transect 4 of the Palm Beach County s Lake Worth Lagoon Fixed Transect Monitoring Program is located just north of the Southern Blvd Bridge on the east side of the lagoon in the vicinity of Mar-a-Lago. Since 2013, the deepest occurrence of seagrass at Transect 4 has been 3.3 ft MLW, and no seagrass was found in the permanent monitoring stations at Station 4 in July Multiple surveys of the Mar-a-Lago Channel have not found seagrass in the proposed dredge area. The shoal area inside the Mar-A-Lago channel was sampled during the 2013 Lake Worth Lagoon Seagrass Mapping Project. Seagrass was not found at the three ground-truthing sites in 2013; and the area was classified as unvegetated softbottom -potential seagrass habitat based on 2007 bathymetry. The current water depths in the proposed dredge area appear to limit the potential for seagrass establishment. Bonefish Cove was sampled on September 14, 2016 as part of Palm Beach County s CAP 35 benthic macroinvertebrate study to compare five restoration sites within the Lake Worth Lagoon with five areas proposed for restoration projects. The benthic community was sampled at two sites within Bonefish Cove to characterize the biological community and sediment environment. A total of 10 cores samples and 10 grab samples were collected for quantification of the benthic community, and two sediment cores were analyzed. The sediment at Bonefish Cove was black muck 100% silt/clay), and muck depth exceeded 1.7 m. Bonefish Cove also had the highest organic content of the 10 study locations at 38.9%. One of the Bonefish Cove sample sites had the lowest overall macrofaunal abundance and diversity of all study sites.

10 Bonefish Cove sediment cores, sampled on September 14, 2016, showing dark muck sediment.

11 2013 Lake Worth Lagoon Seagrass Habitat Map Ü Central Segment 3: *26.7< &7 - < *&, 5 &66 &'.7&7 %32* 3+ *&, 5 & *2 * #29 *, *7&7*) 37*27.&0 *&, 5 &66 &'.7&7 #29 *, *7&7*) 3+ 7'37731 *275 &0 $ *<*) #6*.1.7&7.326 "- * 6*&, 5 &66 430<, 326 : *5 * ) *0.2*&7*) * 80< &2) 8, 867 &*5.& , 5 &4- < '< 9.2*32 2 : *),5 382) , "- * 430<, '*.27*5 45 *7*) &6 &,5 382) , 9 *5.+. & * 1 &4 &2) 237 &6 &2 *; - &867.9 * 39 *5 &, * 3+ 6*&, 5 &66 39 * * &/ * $35 7- &, *).76 *&, 5 &66 '*),5 382) , *< 6 &2) '*) *), * ) *0.2*&7.32 : *5 * 31 40*7*) < 73 &28&5 < '< 3&67& $35 / : &6 4* *) , - & 68' 3275 & 7 &, 5 **1 *27 :.7-3&67 &2) &5 '35 2,.2**5.2, &01 *& < *4&5 71 * *27&0*6385 * &2&, *1 *27 80< *5.&06 : *5 * ) *) '< &01 *& < *4&5 71 * *27&0*6385 * &2&, *1 *27 35 & 31 40*7* ) * *&, 5 &66,5 382) , 1 &4 5 *& *7-3) 6 5 *68076 &2) - &'.7&7 0&66.+. &7.32 ) * *+ * * &663.&7*) = &/ * $35 7- &, 332 *&, 5 &66 &44.2, *435 7>.0*6

12 Transect E EEE 943 E