Choconut Creek Restoration Demonstration Project
SCOPE OF SERVICE
Data Collection
Data collected during the watershed assessment will be augmented by detailed site survey to be provided through a
sub-contract with Shumaker Consulting Engineering & Land Surveying, P.C. (SCE) The existing condition site
survey will be conducted under the direction of an LDG geomorphologist. Survey data will be collected in
accordance with the following procedures and assumptions:
• Perform field survey of 3000' of Choconut Creek streambed to establish project control and collect
planimetric and digital terrain modeling (DTM) data for developing plans and cross sections. The
mapping will encompass the Choconut Creek streambed and extend to approximately 25' beyond the
stream banks throughout the project limits. The mapping bandwidth will be extended for 500' to identify
the flood plain limits.
• Horizontal coordinate values will be based on an assumed datum. Vertical coordinate values will be based
on the National Geodetic Vertical Datum 1929.
• Monumented cross section locations, consisting of rebars with caps, will be established at 8 sites within
the project limits.
• Generate mapping from field survey data in Microstation (.dgn) file format.
• Units of measure will be English.
• Research and property line determination and placement will not be required.
LDG personnel will prepare existing condition plans and generate cross-sections for use in the analysis and design
based on the digital terrain model generated by SCE.
Additional data used in the design includes existing aerial photographs and geomorphic data described below.
Geomorphic Data and Design
The first component of the design is determining the cause of channel instability within the design reach. This
will be completed within the watershed assessment work completed prior to design. Based on the causes of
channel instability, design criteria to address those problems will be generated. LDG will complete data collection
and design of 1700 feet of channel within a 3000-foot reach of stream.
Bankfull discharge for the design reach will be computed using rainfall-runoff models to compute the discharge
resulting from the 1.5, 2, 50, and 100-year recurrence interval storms. These discharges will be correlated to field
observations of the bankfull height to select the computed discharge that is most consistent with the physical
indications of bankfull discharge within the design reach. Once the bankfull discharge has been determined,
possible future changes to the bankfull discharge will be considered prior to beginning design.
Reference reach data will be collected on an appropriate reference reach if an acceptable reference reach can be
located. Reference reach data collection will include field survey, particle size distribution, hydrologic
computations, and aerial photograph reviews. A joint-decision about acceptability of potential reference reaches
will be made with CCWA/CT.
If an acceptable reference reach cannot be located, there are alternated design methods accepted for use. Regional
curve information generated by PADEP, U.S. Fish and Wildlife Service, U.S. Geological Survey, and others will be
used to compute natural channel forms based on the stream's bankfull discharge, sediment load, slope, and
vegetative cover.
Particle size distributions in addition to those completed under the watershed assessment grant will be completed
within the design reach. These distributions will be collected using the modified Wolman Pebble Count method to
determine the particle size within the design reach. Particle size distributions will be collected in three sub-reaches
in the design reach.
A hydraulic analysis of the design reach will be completed using both the existing channel conditions and the
design conditions. This analysis will be completed using the U.S. Army Corps of Engineers HEC-RAS water
surface profile computer model. This model allows the computation of a number of values essential for design.
Bed shear stress will be determined for the bankfull discharge and for larger 50 and 100-year recurrence interval
storms. Shear stress at a variety of locations along the design reach will be used to determine the largest size of
bed material that will be mobilized at a given discharge. Existing condition shear stresses will be compared to
design shear stresses to ensure that sediment transport through the reach meets the design requirements.
Water surface profiles for design conditions generated in the hydraulic analysis are also compared to the existing
conditions for the bankfull discharge, 50-year discharge, and 100-year discharge. This analysis is done to ensure
that flood elevations are not increased by the designed changes to the stream channel.
Final construction ready plans and specifications will be provided to CCWA/CT upon completion of the design.
As-built data will be collected by LDG upon completion of construction. Design modifications made during
construction will be represented on the final as-built plans to be submitted with the final report.
Site Access and Releases
CCWA and CT will be responsible for providing LDG/SCE restoration site access for the duration of the project.
CCWA and CT will be responsible for providing all necessary landowner agreements prior to construction.
Permitting
SCE will complete and submit following applications and forms
• Joint Permit Application for a Pennsylvania Water Obstruction and Encroachment Permit
Application and a U.S. Army Corps of Engineers Section 404 Permit Application
• General Information Form
• Cultural Resource Notice
• Environmental Assessment Form
Incidental to completing these applications and forms, SCE will include the following information:
• Act 14 notification
• Determination of historic and archeological sites
• PNDI search form
• Color photographs
• Adjoining property owners
Information to be completed, as required by permitting agencies, by LDG and provided to SCE for attachment to
the preceding applications and forms is as follows:
• Plans, profiles, sections, and details
• Erosion and sedimentation plan and approval letter
• Hydrologic and hydraulic analysis
• Stormwater management analysis with consistency letter
• Floodplain management analysis with consistency letter
• Risk assessment
• Professional engineer's seal and certification statement, if required
• Alternative analysis
• Mitigation plan
All information will be provided in both hard copy and electronic file format.
SCE will attend the following meetings as part of the permitting process and assumes that all meetings will be held
in Choconut Township.
• Pre-Application Meeting
• End of design meeting
• Permitting meeting
Assume that final submission will require the following printing for distribution:
• Application submission - 3 copies
• Choconut Creek Watershed Association - 1 copy
• LDG and SCE - 1 copy each
SCE has assumed that the Choconut Creek Watershed Association will pay application and permit fees.
Plan and Specification Sets
LDG will provide 5 sets of construction-ready plans and specifications to CCWA/CT. LDG will provide 3 sets of
as-built plans to CCWA.
Design Review Meetings
LDG will participate in six meetings: design review meetings at 25, 50, and 90 of design completion in
addition to the meetings scheduled at the beginning of the project, end of design, and permitting phase.
Project Management
LDG will provide construction stakeout prior to construction and design modification as needed throughout the
construction process. LDG will provide onsite project supervision for up to 15 days to a maximum of 120 hours
during the construction phase. If additional project supervision time is needed, LDG will provide supervision at
the cost of personnel time and expenses. As-built plans will be prepared upon completion of construction.
Final Construction Report
LDG will provide CCWA/CT with 5 bound copies of the final restoration report.