Conservation Commission Meeting Agenda/Materials 109R and 131 Clark Lane Exhibit List (linked)

Joseph R. Theroux 
                                  ~ Certified Forester/ Soil Scientist ~ 
                                   Phone 860-428-7992~ Fax 860-376-6842 
                                        P.O. Box 32, Voluntown, CT. 06384 
                   Forestry Services ~ Environmental Impact Assessments 
             Wetland Delineations and Permitting ~ E&S/Site Monitoring 
                                                               Wetland function and value assessments  
 
 
 
 
 
 
 
 
 
 
 
2/3/2023 
 
Conservation Commission 
Town of Waterford 
15 Rope Ferry Rd. 
Waterford, CT. 06385 
 
Attn: Ms. Maureen Fitzgerald, Environmental Planner 
 
Re: Response to Carya Ecological Services, LLC and SLR International 
Corporation reports. 
 
Dear Ms. Fitzgerald, 
 
I have reviewed the above-mentioned reports, and the most recent set of project 
plans, revised as of 12/5/2022, and I offer the following responses and 
information: 
 
1.) Carya Ecological Services report dated January 26th, 2023: 
 
The report on page 3 states that in my function and value report, I incorrectly 
rated the wetland function of flood storage capacity as low. I must disagree 
with her opinion on this, as the numerous depressions in the topography do not 
constitute significant flood storage capacity or function. 
 
The flood storage capacity of the wetland complex associated with Fenger 
Brook in this area is compromised due to the numerous intermittent watercourses 
and the Brook itself transporting any potential flood flows directly off the site 
with little retention. 
 
This is evidenced by the highly eroded, enlarged streambanks and large exposed 
stones and boulders within and adjacent to the banks. This was noted in my 
report. The depressed areas within the wetlands do seasonally inundate from 
surface runoff and groundwater discharge, and possibly infiltrate during the 
dry season, but the overall sloping topography adjacent to the Brook will not 
store or detain potential flood flows significantly. 
 
The report also states that “Mr. Theroux did not assess the functions and values 
of the wetland system as a whole.” 
 
For my assessment I included the Fenger Brook wetland corridor, focusing 
primarily on the Brook and the forested/scrub-shrub wetlands directly adjacent 
to the Brook and the proposed development. 
 
I do concur that due to the 95 acres of the Bates Wood Park in New London, 
which is publicly accessed property, the additional wetland values of 

recreational and aesthetics are exhibited in this portion of the wetland complex 
but not in the wetlands on the project site. 
 
Overall, I think we are all in agreement that Fenger Brook and the wetland 
system as a whole, is a highly functioning wetland worthy of protection which is 
why I support a conservation easement over the on-site wetlands. The placement 
of a conservation easement will preserve the existing functions and values of 
the wetlands. 
 
Page 3 of the report mentions “forest pools which are expected to be productive 
vernal pools”. 
 
Within the wetlands to the east of the proposed development there are numerous 
depressed areas that inundate seasonally, fed by groundwater and intermittent 
watercourses, however, I do not feel that it is correct to assume that these 
depressions are vernal just because they are inundated depressions.  
 
In my site visits in March, May, and July, I noted no obligate or facultative vernal 
pool species in these areas, in fact I saw no amphibians or reptile species 
altogether.  
 
I do however, believe that a significant amphibian and reptile population exists in 
the on-site wetlands and it warrants protection. 
 
Although not directly addressed in this report, Mrs. Gadwa testified that she had 
concerns that there will be diminished flows to the wetlands along Fenger 
Brook in the northern strip of the subdivision, thus potentially changing the 
hydrology of the wetlands in this area which could cause significant impacts.  
 
I believe this line of thinking is due to the proposed abandonment of the existing, 
(untreated), stormwater discharge from Clark Lane and its incorporation into 
the proposed stormwater treatment system. 
 
It is my professional opinion that this will not be the case, due to the fact that the 
current stormwater discharge does not constitute a significant hydrologic 
input to the wetlands and especially the Brook, as the discharge point is over 300 
feet from the wetland boundary and these discharges infiltrate into the upland 
soils. 
The volumes of stormwater that discharge from the Clark Lane drainage area, 
(2.66 acres), are negligible compared to the vast quantities of groundwater that 
serve as the main source of hydrology to the wetlands. 
 
I believe the proposed grading and stormwater diversion will not significantly 
impact the groundwater hydrology of the wetlands due to the overall distance 
this feature is proposed from the wetlands, and the groundwater breakouts in 
and directly adjacent to the wetlands occur at a much lower elevation, (96’), 
than the higher uplands 300 feet up the slope, elevation (108”).  
 
Mrs. Gadwa is also concerned with the effects of greater quantities of water 
that will be introduced into the southern portion of wetlands below the 
discharge point of the detention basins. She stated that if the water table were 
to go up 5 or 6 inches in elevation, there would be added tree mortality. 
 

I do not agree with this assumption, firstly, the topography throughout the 
discharge area gently slopes to the east, therefore any discharges from the 
outlet and level spreader will sheet flow downgradient from the level spreader 
and thus could not possibly flood to 5 or 6 inches in height or even close to 
that. These flows will not be able to increase the water table that is already at 
or near the surface for the majority of the year. Additions of water will only 
infiltrate when water tables are low, or flow across the surface when they are 
high. 
 
The predominant tree species in this portion of the wetlands are red maple and 
white ash, which are both species that have adapted very well to seasonal 
inundation. 
 
The “ghost forests” Mrs. Gadwa describes are usually tied to ocean/sea water 
levels rising and mixing with fresh water ecosystems, causing tree mortality. This 
can also be caused by beaver dams or activities that impound or inundate areas 
with several feet of water for periods extending for several months or years. I 
do not see this happening on this site because there is no berm or significant 
barrier to impound significant quantities of water before it reaches Fenger 
Brook. 
 
Furthermore, I see no significant impacts to the wetlands from the discharge 
from the level spreader as it is designed to attenuate discharge velocities, 
(estimated by the design engineer to be 28.85 cfs at 1.78 feet per second for a 
100-year storm), and the wide design of the spreader being 60+ feet in width. This 
wide outlet will provide for wider dispersion of flows and infiltration when the 
water table is not at the surface. 
 
It is my professional opinion that the proposed bioretention basin and detention 
basin will function as designed, removing sediments, binding & renovating 
nutrients, metals and hydrocarbons and attenuating flows. The wet bottom 
design will mimic the wetland soil conditions and eventually harbor nitrogen 
fixing bacteria that immobilize and utilize nitrogen.  
 
I think the removal of salt from the snow plowing regimen will also reduce 
potential impacts, but this is just as true for the paved surfaces of Clark Lane 
and the middle school as it is for the development. 
 
If the basin is initially seeded with New England Wetmix or the erosion 
control/restoration mix which is designed for detention basins and wet sites, in 
the portions of the basins that are not fully inundated, the resulting vegetation 
will add to the diversity of wetland habitat and enhance nutrient retention. 
 
It should also be noted that the existing expanse of wetlands between the 
discharge point and Fenger Brook exhibit the wetland functions of 
sediment/toxicant retention and nutrient removal/retention/transformation as 
noted in my report.  
 
      2). SLR International Corporation Report dated January 26th, 2023: 
 
Item #1 on page 6 concerns the wetland delineation line is not contiguous. 
 
This is because in the areas where the delineation line stops, the wetland 
boundaries extend to the east, and in some areas, a significant distance from the 

project, or are located a significant distance off the subject parcel. I think the 
regulated areas are clearly and accurately defined. 
 
Item #2 concerns amphibian and reptile habitat and vernal pool activity. 
 
No reptiles, amphibians or vernal pools were noted in the wetlands that were 
delineated, most likely due to the time of year, however, undoubtedly, there is a 
significant amphibian/reptile population utilizing the wetlands as habitat. 
This habitat will not be disturbed or impacted because no direct impacts or 
disturbance is proposed in the wetlands. The plans depict a significant 50-foot or 
more set back from the wetlands where no disturbance is proposed, except for 
the bio-retention level spreader. I see no impacts to the reptile or amphibian 
populations or habitat from the bio-retention basin or level spreader 
construction, in fact, it will become habitat as well. 
 
I concur that there is a potential for turtle habitat, and a conservation 
protection plan is warranted. The typical construction phase measure for turtle 
and amphibian protection is a properly installed and maintained silt fence. The 
plan should be revised to show a continuous line of fencing for the entire 
eastern perimeter. 
 
Item #3 concerns vernal pools. 
 
I did not observe any vernal pools, nor were any mentioned in the Carya report. 
 
Item #4 concerns a native species planting plan. 
 
I concur, the planting plan shown on sheet #17 proposes native wetland and 
upland herbaceous and shrub species in the detention basins. 
 
I also noted that SLR suggested raising the elevation of the bio-retention basin 
to create a separation from the existing water tables. From my standpoint, I 
would prefer that it be constructed at an elevation so as to cause a wet bottom 
for a short portion of the growing season, to help create and maintain proper 
conditions for the proposed native wetland herbaceous and shrub vegetation. 
 
If you have any questions regarding these concerns or responses, please feel 
free to contact me, 
 
 
Thank you, 
 
Joseph R. Theroux 
 
Joseph R. Theroux 
Certified Soil Scientist 
Member SSSSNE, NSCSS, SSSA.