2014 Bathymetric and Sediment Report Mill Pond Wayland, Massachusetts Lycott Environmental (Lycott) was contracted (Contract # 793-14) by the Wayland Surface Water Quality Commission (WSWQC) to conduct a bathymetric survey and a sediment survey in Mill Pond in 2014. In accordance with this contract, the following document serves as a report to summarize the tasks completed in 2014. METHODS A bathymetric survey was conducted by Lycott on December 4, 2014. Pre-loaded, 5-meter transects were slowly traversed using a small vessel equipped with a sonar device (Lowrance HDS-5 Fishfinder/Chartplotter) (Image 1). Sonar survey methods, including transect width, average speed, ping speed and frequency, closely followed recommendations provided in the ciBioBase User Reference Guide (Contour Innovations, LLC, 2012). In conjunction with the bathymetric survey, water depth and detritus (i.e., soft sediment (decaying organic matter), debris and silt) thickness were measured with an expandable, marked (6� intervals�) PVC rod at 102 point locations throughout Mill Pond (Image 2). Water depth was measured by lowering the PVC rod down through the water column until the detritus was reached. Subsequently, the PVC rod was then pushed through the detritus until hard bottom was reached. The difference between the two recorded depths (i.e., PVC rod measurement to detritus and PVC rod measurement to hard bottom) indicated the detritus thickness at that particular point. Additionally, the GPS location of each point was marked using a hand-held GPS unit (refer to Table 1 for raw data associated with the rod survey). ! ( ( ! ( ! ( !
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Image 1: Orthoimagery of pre-loaded 5-meter transects
January 14, 2015
Image 2: Orthoimagery of 102 rod measurement points
Page 1 of 2
Following this survey, the collected sonar data was processed by a third party, ciBioBase. CiBioBase interpolates the gathered sonar data which results in the creation of continuous (i.e., raster) imagery depicting the bathymetry of the water body. This processed data was further analyzed in a GIS software program (ArcGIS 10.2.2) in order to produce a bathymetric map with one-foot contours displayed. Additionally, the water depth rod measurements collected at the 102 point locations were imported and overlaid on the bathymetry raster imagery in ArcGIS to assess the accuracy of the interpolated bathymetric raster data. Lastly, detritus thickness rod measurements were imported and interpolated in ArcGIS to produce a detritus thickness map with half-foot contour classifications depicted. RESULTS Results of the bathymetric survey indicated that Mill Pond has a maximum depth of 9.6 feet, an average depth of 5.1 feet, and an estimated water body volume of 13.5 acre-feet. In general, the majority of water depth rod measurements were within one foot (70%) and two feet (89%) of the interpolated ciBioBase bathymetric imagery output. Detritus thickness throughout Mill Pond averaged 0.72 feet, and a maximum of 4 feet was noted at the inlet location in the northern most section of the pond. Maps depicting the bathymetric and detritus thickness at Mill Pond are enclosed. CONCLUSION/RECOMMENDATION Excessive detritus buildup was noted at the inlet (0.28-acre area) and outlet (0.57-acre area) locations of Mill Pond, and to a lesser extent, along the shorelines of the central portion of the pond (0.76-acre area). In comparison to the rest of the pond, these areas would benefit most from hydro-rake management/detritus removal (refer to ‘Figure 3: Proposed Management Areas’ map). Removal of this excessive material will benefit this open water habitat via the removal of nutrients, increasing water retention, and reducing the rate of eutrophication in Mill Pond. Estimates for the 2015 management season are enclosed.
2014 Mill Pond Report January 14, 2015
Page 2 of 2
Fi gu re1:Bathym etri c Su rvey Map Legend
1-foot contour* 9' - 9.6' 8.0' - 8.9' 7.0' - 7.9' 6.0' - 6.9' 5.0' - 5.9' 4.0' - 4.9' 3.0' - 3.9' 2.0' - 2.9' 0' - 1.9' Note: Contour intervals initate at 2' in order to improve legibility of the map.
Mill Pond Wayland, MA
DataCol l ec ted:12/ 4/ 14 MapPrepared: 1/ 1 1/ 15 For WSWQC( #79314) Bas em ap© 2013Es ri
0
35
70
1: 1, 250 Feet
140
±
21Wes t Mai n Street • Spen c er,MA 5088850101• i n fo@l yc ott. c om
Fi gure 2:Detri tus Thi cknes s Ma p Legend Detritus Thickness (ft.) <0.5 0.5 - 1 1 - 1.5 1.5 - 2 2 - 2.5 2.5 - 3 3 - 3.5 3.5 - 4
Half foot contours
Mill Pond Wayland, MA
Da ta Co llected:12/ 4/ 14 Ma p Prep a red: 1/ 12/ 15 Fo r WSWQC( #79314) Ba s ema p © 2013Es ri
0
35
70
1: 1, 250 Feet
140
±
21Wes tMa i nStreet• Sp enc er,MA 5088850101• i nf o @lyc o tt. co m
Figure 3: Proposed Management Areas Legend Primary
Secondary Note: Primary areas = highly recommended for removal of detritus Secondary area = less highly recommended for removal of detritus
Mill Pond Wayland, MA
Data Collected: 10/4/2014 Map Prepared:1/06/2015 For Wayland Surface Water Quality Committee (WSWQC) Basemap © 2013 Esri
0
35
70
1:1,350 Feet
140
±
21 West Main Street • Spencer, MA 508-885-0101 • info@lycott.com
Table 1: Mill Pond 2014 Water Depth and Detritus Thickness Rod Measurements Raw Data
January 13, 2015
PT ID
Latitude (DD)
Longitude (DD)
Water Depth to Soft Bottom (ft.)
Water Depth to Hard Pan(ft.)
001
42.367425
-71.357472
7
7.5
Detritus (ft.) (Soft Bottom â&#x20AC;&#x201C; Hard Pan) 0.5
002
42.367407
-71.357488
7
8
1.0
003
42.367409
-71.357636
6
6.5
0.5
004
42.367519
-71.357760
6.5
7
0.5
005
42.367563
-71.357614
7
7
0.0
006
42.367603
-71.357522
6.5
6.5
0.0
008
42.367656
-71.357372
7.5
8
0.5
009
42.367601
-71.357413
7
8
1.0
010
42.367561
-71.357546
4.5
5
0.5
011
42.367565
-71.357727
2.5
2.5
0.0
012
42.367729
-71.357670
7
7
0.0
013
42.367828
-71.357647
9
10
1.0
014
42.367750
-71.357416
6.5
6.5
0.0
015
42.367809
-71.357384
7
7
0.0
016
42.367739
-71.357458
9
9.5
0.5
017
42.367727
-71.357639
6.5
6.5
0.0
018
42.367676
-71.357758
4
6
2.0
019
42.367714
-71.357860
2
2
0.0
020
42.367802
-71.357792
6.5
7
0.5
021
42.367889
-71.357668
9
10.5
1.5
022
42.367879
-71.357557
9
10.5
1.5
023
42.367919
-71.357384
7
7
0.0
024
42.367970
-71.357423
4
6
2.0
025
42.367924
-71.357523
8.5
8.5
0.0
026
42.367904
-71.357724
9
9.5
0.5
027
42.367845
-71.357839
7
7.5
0.5
028
42.367848
-71.357932
4.5
5.5
1.0
029
42.367924
-71.358035
3.5
3.5
0.0
030
42.368060
-71.357928
6.5
7.5
1.0
1
January 13, 2015
PT ID
Latitude (DD)
Longitude (DD)
Water Depth to Soft Bottom (ft.)
Water Depth to Hard Pan(ft.)
031
42.368107
-71.357745
7.5
8
Detritus (ft.) (Soft Bottom â&#x20AC;&#x201C; Hard Pan) 0.5
032
42.368118
-71.357620
6.5
7.5
1.0
033
42.368140
-71.357539
5
6
1.0
034
42.368168
-71.357563
5
5.5
0.5
035
42.368094
-71.357729
7
7
0.0
036
42.368078
-71.357785
7
7.5
0.5
037
42.368057
-71.357922
5.5
6
0.5
038
42.368031
-71.358040
2.5
5
2.5
039
42.368082
-71.358112
2.5
3
0.5
040
42.368202
-71.357971
6
6
0.0
041
42.368195
-71.357803
6.5
6.5
0.0
042
42.368227
-71.357717
5.5
6
0.5
043
42.368176
-71.357596
6
6
0.0
044
42.368219
-71.357598
4.5
5.5
1.0
045
42.368294
-71.357730
5
5
0.0
046
42.368242
-71.357726
5
5
0.0
047
42.368233
-71.357857
7
7
0.0
048
42.368268
-71.358031
6.5
7.5
1.0
049
42.368321
-71.358080
4.5
5
0.5
050
42.368457
-71.357956
4
4.5
0.5
051
42.368477
-71.357865
6
6
0.0
052
42.368478
-71.357769
7
9
2.0
053
42.368462
-71.357669
5.5
5.5
0.0
054
42.368476
-71.357666
1.5
3.5
2.0
055
42.368569
-71.357800
4.5
4.5
0.0
056
42.368550
-71.357699
6
6.5
0.5
057
42.368536
-71.357782
4.5
5
0.5
058
42.368512
-71.357849
4.5
5
0.5
059
42.368514
-71.357922
4
4.5
0.5
2
January 13, 2015
PT ID
Latitude (DD)
Longitude (DD)
Water Depth to Soft Bottom (ft.)
Water Depth to Hard Pan(ft.)
060
42.368669
-71.357997
2.5
4
Detritus (ft.) (Soft Bottom â&#x20AC;&#x201C; Hard Pan) 1.5
061
42.368729
-71.357865
4.5
4.5
0.0
062
42.368696
-71.357732
4.5
5.5
1.0
063
42.368659
-71.357688
2.5
3.5
1.0
064
42.368709
-71.357666
3.5
4.5
1.0
065
42.368750
-71.357774
3
5
2.0
066
42.368742
-71.357824
2.5
4
1.5
067
42.368811
-71.357849
2.5
4
1.5
068
42.368859
-71.357734
2.5
5
2.5
069
42.368855
-71.357671
1.5
3.5
2.0
070
42.368893
-71.357652
1.5
4
2.5
071
42.368906
-71.357680
2
5
3.0
072
42.368953
-71.357865
2
4
2.0
073
42.369025
-71.357824
1
4.5
3.5
074
42.369037
-71.357816
1.5
4.5
3.0
075
42.369059
-71.357628
1.5
3.5
2.0
076
42.369074
-71.357631
1
3
2.0
077
42.369209
-71.357713
2
3.5
1.5
078
42.369259
-71.357734
1
1.5
0.5
079
42.369236
-71.357737
1
5
4.0
080
42.369119
-71.357794
1.5
2
0.5
081
42.369083
-71.357843
1
4.5
3.5
082
42.367047
-71.357292
5.5
7
1.5
083
42.367105
-71.357228
5.5
6
0.5
084
42.367175
-71.357190
5.5
7.5
2.0
086
42.367089
-71.357057
4.5
5
0.5
087
42.366939
-71.357103
3.5
6
2.5
088
42.366864
-71.357131
3
5
2.0
089
42.366861
-71.357116
1.5
2
0.5
3
January 13, 2015
PT ID
Latitude (DD)
Longitude (DD)
Water Depth to Soft Bottom (ft.)
Water Depth to Hard Pan(ft.)
090
42.367011
-71.357162
1
2.5
Detritus (ft.) (Soft Bottom â&#x20AC;&#x201C; Hard Pan) 1.5
091
42.367425
-71.357472
5.5
5.5
0.0
094
42.367407
-71.357488
7
7.5
0.5
095
42.367238
-71.357147
6
6
0.0
096
42.367210
-71.357201
6.5
8
1.5
097
42.367172
-71.357234
7
7
0.0
098
42.367208
-71.357398
7
7.5
0.5
099
42.367281
-71.357408
6.5
7.5
1.0
100
42.367310
-71.357316
7.5
7.5
0.0
101
42.367352
-71.357317
7
7.5
0.5
102
42.367355
-71.357375
7
8
1.0
103
42.367304
-71.357475
6.5
6.5
0.0
104
42.367311
-71.357500
7.5
9
1.5
105
42.367366
-71.357515
7
7.5
0.5
106
42.367388
-71.357465
6.5
7.5
1.0
4
The mechanical hydro-raking project would span three years if the two primary areas (Inlet and Outlet) and the secondary area (Center) of pond were adopted as proposed. Based on sediment probing measurements collected on December 4th, there is an average of 2.13 feet (Inlet), 1.05 feet (Outlet) and 1.43 (Middle) of collected detritus (debris, leaf litter, organic decaying matter, soft sediment, silt). Below is a table estimating the amount of detritus removal and the duration of each hydro-rake event based on location. Proposed Detritus Removal Area Inlet Outlet Center
Acre Area 0.28 0.57 0.76
Avg. Detritus Depth (ft) 2.13 1.05 1.43
Material yds3 (Wet) 962 953 1,752
Estimate Material Removal* 641 635 1,168
Estimate yds3 (Dry)** 160 159 292
Estimate Rake Time (Days)*** 4-5 5-6 8-9
* Assumes two-thirds of material can be effectively removed by hydro-raking ** Assumes material will de-water by at least 50% immediately upon removal and another 25-35% prior to ***
disposal Estimate hydro-rake days dependent on transportation time of material to off-load location
Anticipated costs are outlined in the table below: Mgmt. Task NOI
Detritus Removal
On-shore Material Collection / Disposal
Activity Description
Cost
Prepare and submit a NOI to MassDEP and the Wayland Conservation Commission (includes attendance at NOI hearing, does not included fee to obtain certified abutters list, certified abutter mailing and public hearing notice in local newspapers – up to $500 in additional costs).
$2,000
Note: The NOI may require an aquatic vegetation survey and wildlife habitat survey. Mobilization / Demobilization - $1,500 Daily rake fee for 7.5 on -water operating hours - $1,500 Purchase and installation of erosion control measures along shoreline of offload area - $500 Use and installation of turbidity / fragment curtain at outlet - $0 Onsite stockpiling and composting per week with use of dewatering tub and rental of Bobcat Versahandler with operator Onsite dewatering in containers with rental of Bobcat Versahandler with operator and offsite disposal / composting
$9,500 (Inlet) $9,500 (Outlet) $13,500 (Center)
$2,500 (Inlet) $2,500 (Outlet) $5,000 (Center) $6,000 (Inlet) $6,000 (Outlet) $12,000 (Center)