 |
DISTRICT OF COLUMBIA WATER AND SEWER AUTHORITY
5000
OVERLOOK AVENUE, S. W., WASHINGTON, D.C. 20032
|
JAN
2 9 2003
Councilmember
Kathy Patterson (Ward 3)
John Wilson Building
1350 Pennsylvania
Avenue, NW - Suite 107
Washington,
D.C. 20004
SUBJ:
Planned Engineering Solutions for Sewers in the C&O Canal National
Historical Park and the Palisades Community
Dear
Councilmember Patterson:
The
District of Columbia Water and Sewer Authority (DC WASA) has received
letters and other correspondence from you as well as from citizens of
the Palisades community identifying concerns regarding several sewers
along the C&O Canal National Historical Park, Clara Barton Parkway,
and within the Palisades community. DC WASA recognizes that odors and
aging sewers in this area have affected Palisades' residents and Park
users. DC WASA has evaluated issues reported from these areas and has
developed long-term solutions to effectively control odors and repair
these sewers, while maintaining the overall integrity of the sewer system
infrastructure.
As
you may be aware, DC WASA has met with Ward 3 community members to evaluate
sewers, and to explain our engineering solutions for controlling odors
in these areas. At the ANC-3 meeting on November 6, 2002, Mr. John Trypus
of my staff presented the odor study, interim odor controls, and the long-term
og9rabatement program1~t.he Potomac Interceptor (PI) sewer along the C&O
Canal from Fletchers Boathouse in the D1strict of Columbia to the Great
Falls National Park in Maryland. As a follow-up to that meeting, DC WASA staff met with several community members of the Palisades community
on November 21,2002 to evaluate odor issues near the intersection of Manning
Street and Potomac Avenue, NW, sewer odors along the C&O Canal at
Chain Bridge, and aging sewers under Chain Bridge and along Discovery
Creek near Fletchers Boathouse.
A
summary of the planned engineering solutions is provided below for the
sewer odor concerns and aging sewers identified during discussions, email
correspondence, and site visits with members of the Palisades community.
I assure you that DC WASA has fully evaluated the issues raised by the
citizens of Ward 3, and that we are actively working towards the installation
of these controls and needed repairs. DC WASA is committed to the long-term
operation and maintenance requirements needed to ensure that the planned
odor controls and sewer pipe repairs are adequate well into the future.
-
2-
Potomac
Interceptor Sewer
- DC WASA has been worked with
the Metropolitan Washington Council of Governments (MWCOG) since 1998
to assess the physical condition, hydraulic capacity, and long-term planning
goals of the PI. The extensive evaluation of odors being released from
the PI began in April 1999, which resulted in the completion of a formal
Odor Study with recommendations to control odors from the PI on an interim
and long-term basis. The Odor Study, completed by our Consultant in March
2000, indicated that there was no acute or chronic health effects associated
with the low levels of odorous gas being released from the PI vents. Interim
odor controls were installed along several of the C&O Canal vents
between May and July 2000 to provide some odor relief during the development
and implementation of the long-term odor abatement program, which are
currently being maintained on a quarterly basis by DC W ASA. The long-term
odor controls are expected to be installed and operating by May 2005,
which will provide odor control by sealing multiple vents and installing
four odor control vacuum blower facilities along the PI. As the long-term
odor abatement program involves the construction of several odor control
facilities within the National Park Service property, the design and construction
efforts must meet all required federal mandates under the National Environmental
Policy Act, the National Historic Preservation Act, the Archeological
Resources Protection Act, and other regulatory requirements. More information
and details of the comprehensive PI long-term odor abatement program can
be found on the project web site
www .potomacintercetor.com
Manning
Place and Potomac Avenue, NW
- DC WASA developed an odor control plan
for several venting manholes near Manning Street and Potomac Avenue, NW
(i.e., Potomac Heights Trunk Sewer) after meeting with Palisades's community
members on November 21, 2002. The odor control plan involves sealing several
manhole cover pick holes and installing and maintaining activated carbon
filters at two locations along the Potomac Heights Trunk Sewer. Due to
the age of the sewer and dynamic flow characteristics, DC WASA must perform
a condition assessment of the sewer prior to the installation of the proposed
odor controls. A condition assessment is required because some odor-causing
compounds can lead to corrosive conditions in sewers causing possible
structural failures. It is important that DC WASA ensures the adequate
and reliable conveyance of sewage as our first priority prior to the control
of nuisance odors. DC WASA anticipates that the recommended odor controls
for the Potomac Heights Trunk Sewer will be installed within the next
six months.
Chain
Bridge Sewer ( Pimmit Run
Siphons) - There are
two sewers under Chain Bridge that provide the conveyance of wastewater
from Fairfax County to DC WASA for treatment at the Blue Plains Advanced
Wastewater Treatment Plant. The age of these sewers and the environment
has led to the deterioration of the twin steel pipes under Chain Bridge.
DC WASA is currently working with Fairfax County to implement needed
repairs of these sewers within the next several months. In addition,
the replacement of these two sewer pipes with new pipes is being completed
over the next two years by Fairfax County, in conjunction with the replacement
of three water mains under the bridge by Arlington County.
Discovery
Creek Sewer - The Discovery
Creek sewer conveys flows from the Palisades area to the Potomac Interceptor
sewer at a connection point near Fletchers Boathouse. Stream bank erosion
along the sewer has lead to settling of the pipe, which caused a joint
to be offset and a manhole to become unstable.
- 3-
DC
WASA has evaluated this condition in the past and completed repairs to
the sewer several years ago, and recently completed additional repairs
to stabilize the sewer section. Detailed inspections of the sewer have
indicated that additional, more comprehensive repairs are required. DC
WASA is currently developing an acceptable engineering solution to repair
the undermined section of the Discovery Creek sewer. It is anticipated
that the evaluated section of the sewer will be permanently repaired within
the next six months, pending the approval of associated permits by the
National Park Service.
Please
feel free to contact Mr. John Trypus in our Planning & Design Branch
should you have any additional questions regarding the engineering solutions
identified in this letter.
Mr.
Trypus can be reached on (202) 787-2406 or JTrypus@dcwasa.com. It is DC
WASA's goal to expedite the :planned engineering solutions as quickly
and efficiently as quickly while meeting the permitting requirements and
mission of the National Park Service to protect the C&O Canal National
Historical Park and the Clara Barton Parkway. Lastly, I thank you and
the other Ward 3 citizens for your letters and your interests in improving
the sewer infrastructure in the District.
cc:
Michael Marcotte , Chief Engineer / Deputy General Manager,
DCWASA
Cuthbert Braveboy , Director of Sewer Services, DCWASA
Leonard
Benson, Director of Engineering and Technical Services, DCWASA
Debby
and Alex Wheeler, Palisades Community, Ward 3
Stephen
Day, Palisades Community, Ward 3
Sally
Strain, Palisades Community, Ward 3
Loretta
Guarda , Palisades Community. Ward 3
Robert
Sinclair, Palisades Community, Ward 3
|
