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Phase I Stormwater Pollution Prevention
Plans
HRP has prepared over 100 Stormwater Pollution Prevention Plans
(SPPPs) under the Phase I regulations governing run-off from
"industrial activity." Plans have been prepared to comply with
both the federal Multi-Sector General Permit and individual
states' general permits.
Examples of specific industry facilities include:
The SPPPs have
defined run-off patterns and mapped collection/discharge
facilities, identified potential pollutant sources, and
recommended appropriate Best Management Practices (BMPs) to
improve run-off quality. The Plans have also included detailed
monitoring plans to evaluate SPPP effectiveness. Monitoring
requirements under the federal permit and some state permits are
minimal, however, some states' programs require extensive
sampling, laboratory testing, and reporting. Based on results,
HRP has implemented these monitoring plans, interpreted results,
and negotiated with regulators for our clients to initiate site
improvements and implement additional BMPs.
Combined Sewer & Storm Sewer
Monitoring, Wethersfield Cove, Hartford, CT
HRP Associates, Inc. conducted a water quality survey of
Wethersfield Cove, a significant recreational resource in the
Hartford area. The Cove receives combined sewer overflow,
stormwater and surface runoff from a large highly urbanized
drainage basin. A series of five dry weather, five wet weather
and two intensive bacterial sampling events were conducted at a
total of eight locations. Some locations were accessible by land
and some by boat only. Field measurements were made of water
temperature, conductivity and dissolved oxygen, and samples were
collected for laboratory analysis. Hydrologic and meteorological
field conditions were documented for each survey event.
HRP prepared monthly progress reports which provided the client
with all test results, procedural documentation and results
interpretation. Field Services and Engineering project managers
attended regular project meetings to discuss the project and its
progress. This was a highly visible public project which
required HRP’s interaction with officials from several political
jurisdictions, and the press and public.
Sewage Treatment Plant Modifications, US
Navy, Winter Harbor, ME
HRP Associates, Inc. performed an analysis of sewage treatment
plant deficiencies and design plans for modifications to the
45,000 gpd Winter Harbor wastewater treatment plant. The main
deficiencies included plant hydraulic profile, fouling of the
roto strainer, operating difficulties with the rotating
biological contactors (RBCs), heating/ ventilation/humidity
control, and sludge conveyance difficulties. HRP evaluated the
options of replacing the RBCs with an extended aeration system
or new RBCs. It was determined that new step-fed, larger
capacity RBCs, preceded by primary treatment, was a more
cost-effective option than extended aeration, and required less
operator attention.
The modifications also included new oil fired heaters and
humidity control systems necessary to control excessive moisture
and equipment deterioration. The sludge pumps were modified to
be positive displacement plunger type. A new control panel was
designed to assist with plant operations.
SPDES & NPDES Permitting, Private
Industry, Connecticut
HRP audited this helicopter rehabilitation and production
facility to determine water usage, wastewater generation, and
permitting requirements. Sample collection and analysis for all
proposed discharges was conducted to determine General Permit
eligibility and potential treatment needs.
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NPDES and
SPDES permit renewal applications and General Permit
registrations were completed for the corporation. The
discharges which were identified included: tumbling and
cleaning wastewater (3); air compressor, vacuum pump,
and air conditioner condensates; paraffin waxing rinse
water and hot water bath; non-contact cooling water (7);
metal finishing wastewater (on-site treatment plant);
water softener backwash; cadmium plating line and
cyanide immersion rinse tank discharges to on-site
treatment plant; and boiler blowdown. |
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Related projects completed by HRP included: preparation of a
Discharge Toxicity Evaluation for non-contact cooling water;
upgrade of pH and flow monitoring equipment; and investigation
of modifying the existing SO2 chromium reduction system to a
sodium metabisulfate system. HRP prepared public notices
required for permit renewals and provided on-going engineering
support until final issuance of all permits.
Dam Evaluation & Repair, Roraback Dam,
Harwinton, CT
HRP completed a hydrologic and hydraulic analysis of the
Roraback Dam's watershed and utilized a HEC-II dam-break flood
model to determine the affects a dam failure would have on
downstream communities. After performing a slope stability
analysis using field data from site borings, it was determined
that the dam had an inadequate safety factor due to a failing
core wall and needed to be replaced.
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HRP
developed construction plans and specifications for the
replacement of the earthen dam, as well as construction
staging details indicating how the existing structure
should be removed. The new dam was equipped with a
concrete spillway and outlet, works, and an energy
dissipater located in the outlet channel. A diversion
structure and pipe was incorporated into the design to
divert flow from nearby Leadmine Brook to the reservoir
during periods of low flow were also incorporated into
the project. |
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Using HEC-II, HRP performed backwater analyses of the brook for
both flood (100-year), average annual, and drought conditions
(7Q10) in order to engineer an effective diversion system.
The project was constructed using the design plans and
specifications prepared by HRP. The result has been a safe dam
which has preserved a valuable State resource.
Stormwater Drainage Channel
Improvements, City of Bristol, CT
HRP was selected by the City of Bristol to help correct a
significant drainage problem in the Stafford Avenue area.
Roughly 1800 lineal feet of an open-flow storm-water channel
(tributary of Copper Mine Brook) overflows frequently during wet
seasons and heavy rainfall, and has flooded certain residential
properties.
As a tributary of Copper Mine Brook, there is an open-flow
stormwater channel situated between Stafford Avenue and Brook
Street. This 1800-foot long channel has caused flooding of
certain properties, and HRP was retained to help correct the
deficiencies. Field survey has been performed to locate drainage
features and prepare base mapping, and our civil team is
evaluating drainage characteristics and anticipated flows.
HRP is currently engaged in a program to design channel
improvements. After we perform a thorough survey of the channel
and adjacent properties and flag any wetlands, a drainage
evaluation will be performed. HYDRAFLOW 2002 software (for Storm
Sewers and hydrographs) will be used to model existing
conditions, define the watershed, evaluate capacity and
hydraulic characteristics.
HRP will then develop alternative design improvements for the
channel, and assist the City with permitting requirements.
Design documents will be prepared for improvements to clean and
stabilize the channel, eliminate flooding, and obtain the
required permits for local wetlands and the CTDEP. A U.S. Army
Corps category II permit will also be prepared for the
improvements.
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The City
needs the work accomplished in a timely manner, and at
reasonable cost. Since HRP can provide survey,
geotechnical expertise, civil and drainage, and
permitting assistance all in-house with the most
up-to-date-software, we were able to reduce project cost
and help the City meet their budgets. |
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Water Main Extension, Town
of Wolcott, CT
HRP Associates, Inc. completed environmental assessments and
permitting for a 10,000 foot, 12-inch water main extension in
the Town of Wolcott. The project included two crossings of the
Mad River. The extension brought water supply to areas impacted
by groundwater contamination. A State grant helped fund the
construction.
State and federal wetland boundaries were delineated at both
crossings of he Mad River and application was made for both
local and federal wetland permits, including an Army Corps of
Engineers Category II Program General Permit (PGP). An erosion
and sedimentation control plan, and a temporary construction
dewatering and diversion plan were developed. The PGP was issued
by the Army Corps. HRP also prepared a Connecticut Department of
Environmental Protection (CT DEP) Flood Management Certification
application. As part of this application, impacts of the project
on the 100-year flood plain and flood way were evaluated.
To comply with requirements of the Connecticut Environmental
Policy Act (CEPA), an Environmental Assessment (EA) was prepared
for and accepted by CT DEP. Elements of the project which were
documented in the EA included population projection, the need
for the project and possible alternatives. Potential
environmental impacts (temporary and permanent) were thoroughly
assessed including air and water quality, wetland disturbance,
socio-economic effects and historic/archaeologic sites. Project
alternatives including do-nothing and new supply well
installation were evaluated. Mitigative measures were developed
and documented in the Assessment. Construction of the project
was completed on time and within budget and in full compliance
with permit conditions.
Water Intake Pumps &
Filtration Plant Upgrade, US Navy, Cutler, ME
HRP Associates, Inc. performed the evaluation and preparation of
design plans for the upgrade of a 40,000 gpd water filtration
plant. The existing plant draws water from a shallow reservoir
and an on site well which is considered to be groundwater under
the influence.
HRP evaluated the plant equipment, operating records and
interviewed plant personnel. HRP also conducted sampling
analysis of the raw water and conducted jar testing. The design
of the plant upgrade includes: replacement of raw water intake
pumps, addition of in-line mixing units, replacement of the
flocculation unit, construction of a new bermed chemical
feed/storage area, replacement of all chemical feed
pumps/mixers, upgrading of the power distribution panel,
replacement of the process control panel and all related piping,
electrical, and mechanical systems.
In order to address the taste/odor conditions associated with
the shallow reservoir, HRP's design provided for the addition of
powder-activated carbon which was added upstream of the
flocculation unit and settled out in the clarifier. Additional
sand bed capacity was added to handle the increase in solids
from the carbon addition.
For more
information, please contact
Joseph
Magdol, P.E. at 1-800-246-9021
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