requirements contracts for engineering design and related services ...

noted and reconciled, wherever possible, prior to the commencement of Seepage Basin and/or Highway Drain
design.
f) The Consultant shall study the area contiguous to the project and shall:
1) Define and measure the tributary drainage areas;
2) Develop storm water run-off factors based on actual field conditions; and
3) Calculate design run-off and hydraulic flow rates for each proposed seepage basin and/or highway
drain using the appropriate New York City Department of Environmental Protection design criteria;
g) The Consultant shall develop a soil boring locations plan to supplement the available soil data, as needed to
complete the design of each proposed seepage basin, and shall incorporate said locations into the Subsurface
Exploration Program provided for in this Contract;
h) The Consultant shall coordinate the design proposals with private utilities and the Department of Environmental
Protection to identify and mitigate utility interference issues relative to proposed borings, seepage basin and
highway drain locations, and shall incorporate approved utility accommodation work into the contract documents;
i) The Consultant shall review the soil samples and the results of the soils analysis, soil classification and
permeability tests as obtained under the Subsurface Exploration Program, and shall determine the capacity of the
soils to drain storm water at each proposed seepage basin location. The Consultant’s review shall include:
1) All diaries, logs, test results, boring location plans, etc.;
2) The soil samples and soil classification and analysis results;
3) The results of soil permeability tests.
j) The Consultant shall design the proposed seepage basin and/or highway drains system to accommodate the
design storm water run-off including the depth and diameter of the seepage basins to be installed at each location;
and/or the invert elevations, sizes and drain pipe material to be used, along with all manholes, and drain pipe
support and protection required.
k) The Consultant shall assemble information, tests and analyses obtained, and shall prepare a Seepage Basin
Design and/or Highway Drain Letter Report containing the compilation and analysis of data obtained, recommended
locations for seepage basins and/or highway drains, including approximate street grade elevations (based upon a
coordinated review of grades in conjunction with all other street design tasks included in the Specific Requirements
of this Contract), basin depths, types of seepage basins, approximate seepage basin array(s), and proposed
construction.
l) The Consultant shall submit a draft of the Seepage Basin and/or Highway Drain Design letter report to the
Commissioner for review and approval, and shall make revisions as the Commissioner may require.
m) Upon approval of the draft report by the Commissioner, the Consultant shall hand-deliver to the Commissioner
three (3) copies of the Seepage Basin and/or Highway Drain Design letter report, and original notes, sketches,
calculations, etc., used in the preparation of the Report.
n) The Consultant shall prepare Preliminary Seepage Basin and/or Highway Drains, Catch Basin and Basin
Connection Construction Contract Documents including plans, specifications and Consultant's Estimate in
accordance with the approved letter report, and shall submit the preliminary plans to the Commissioner, relevant
City agencies, and to the utility companies for review comments and utility impact assessment and mitigation.
o) The Consultant shall modify locations as required and incorporate appropriate comments into the Seepage
Basin and/or Highway Drains design, and shall prepare Final Seepage Basin and/or Highway Drains Construction
Contract Documents, including plans, specifications, Consultant's estimate, etc., for incorporation into the Contract
Documents of the Project in accordance with the Street Design Element contained in the Specific Requirements of
this Contract.
NYC Department of Design and Construction
Infrastructure, October 2012
GR-61