Section H Project Description Narrative

Transcription

1 Section H Project Description Narrative Permit No. Pennsylvania Department of Transportation, Engineering District 2-0, 1924 Daisy Street Extension, P.O. Box 342, Clearfield, PA S.R. 2004, Section A03 structure replacement over Duck Run in Lamar Township, Clinton County, Baltimore ACOE District, (Mill Hall, PA Quadrangle: N, W) The applicant proposes to remove the existing bridge and appurtenant structures and to construct and maintain a bridge stream enclosure with concrete wing walls having a single waterway opening of a span and a 7.05 rise, and in length. Place Rock, class R-6 at the wings and abutments of the stream enclosure.

2 INTRODUCTION a. Description of Proposed Activity This report is for the hydrologic and hydraulic analysis for the structure located at Sta of S.R in Clinton County, Pennsylvania. The project includes the replacement of an existing bridge, which carries S.R over Duck Run. b. Project Purpose The purpose of this project is to improve the roadway geometry and replace the structure facility on S.R for public use. c. Effects of the Project on Public Health, Safety and the Environment This project will improve public health and safety along S.R The impact on the environment during construction will be minimized. d. Statement on Water Dependency This project involves construction of a roadway and replacement bridge and is water dependant. e. Purpose of This Report The purpose of this report is to present a hydrologic and hydraulic analysis for the reconstruction of a section of S.R and sizing the replacement bridge. The Pennsylvania Department of Transportation's Design Manual, Part 2, Chapter 10, will be used as a guide in the preparation of this report. f. Structures See Site Data, page H4. g. Traffic Control A detour will be utilized for construction of the proposed structure. Temporary roadways or stream crossings are not required for this project. h. Hydrology A FEMA Flood Insurance Study has been prepared for the Township of Lamar along Fishing Creek. A detailed study was not performed on Duck Run; however the stream drains into Fishing Creek within the study area. The structure is designed based on the hydrology of Duck Run at the structure location. The structure was also checked to determine the impact Fishing Creek has on Duck Run. See Section L for more information.

3 i. Stream Characteristics Duck Run is not listed in PaDOT's Design Manual, Part 2, Appendix 10.A, as a stockable warm water or a trout stream. However, Fishing Creek at the confluence of Duck Run is classified as a Class A wild trout stream (HQ-CWF) in PA Code, Title 25, Chapter 93, Water Quality Standards. The Manning s n-values used in the analysis were determined based on site view.

4 SITE DATA 1. PROJECT LOCATION This bridge replacement project is for the structure located at Sta in Lamar Township, Clinton County. The structure carries S.R over Duck Run. a. Location Map Figure G-1 is the Location Map for this project. Figure G-1 is a portion of the Mill Hall, Pennsylvania, 7 ½ quadrangle of the U.S.G.S. Maps. It indicates the location of the project site on S.R in reference to natural areas and landmarks, political boundaries and other geographic and physical features. 2. EXISTING STRUCTURES a. Location The proposed structure location is the same as that of the existing structure. The project site is shown on Figure G-1 and as noted in the following sections. b. Structure Descriptions The nearest upstream structure is beyond 500 upstream of the project site. It is not anticipated that our project will have an effect on the nearest upstream structure. Existing Structure (To Be Removed) Type: Concrete encased I-beam bridge No. of Span(s): 2 Normal Span(s): 19.0 feet + Underclearance: 7.05 feet + Skew: c. Stream Comparison The proposed structure will be constructed in the same general location as the existing structure. The abutments were pulled out of the stream and the roadway was widened. The roadway grade was set so as to allow for the proposed low beam to minimally match that of the existing low beam. d. Status of Existing Structures The existing structure will be removed for construction of this project. 3. HIGHWATER MARKS AND HISTORICAL FLOOD RECORDS Local residents indicated that the existing structure has never been overtopped. They also indicated that high water conditions are caused by Fishing Creek backwater. There are no

5 apparent high water marks on the existing structure, however there are high water marks present on the barn adjacent to Duck Run and downstream of the bridge. 4. ENVIRONMENTAL HABITATS Duck Run is not listed, however, Fishing Creek is listed as a Stockable Warm Water and Trout Stream in Clinton County (according to Design Manual Part 2, Chapter 10). Duck Run is listed as an High Quality Waters (HQ) and Cold Water Fishes (CWF) in PA Code, Title 25, Chapter 93, Water Quality Standards. 5. DRIFT, ICE, NATURE OF STREAMBED, AND BANK STABILITY a. Drift and Ice The pier, on the existing structure, provides opportunity for debris and ice to accumulate at the upstream side. The proposed option is to remove the 2 span existing bridge and replace it with a single span option. Therefore, drift and ice are not considered a detrimental factor in the hydraulic analysis of Duck Run. b. Nature of Streambed Based upon a site view, the stream banks appear to be stable and the streambed appears to be in good condition. A Manning s n-value of 0.04 was selected for the channel based upon the HEC-RAS manual which references Chow, c. Stream Bank Stability Duck Run has continuous flow. The bank slopes are stable. See photographs. 6. PHOTOGRAPHS Photos 1 through 6, inclusive, are photographs of the existing structures, including the stream and the floodplains. A plan is included to indicate the location of photographs. 7. FACTORS AFFECTING WATER STAGES a. High-water from other Streams Local residents stated that the high water marks on the nearby barn are as a result of high backwater from Fishing Creek. b. Reservoirs There are no reservoirs affecting the project site. c. Flood Control Projects There are no major flood control projects in Duck Run affecting this project.

6 d. Tides Not applicable to this project. e. Other Controls None in the floodplains affected by this project. 8. DEBRIS Debris accumulation is not considered to be detrimental to this project. 9. SITE INSPECTION RECORDS David Piccolomini and Perry Schweiss of SP&K performed a field view on June 20, DESIGN FIELD VIEW APPROVAL Pending. Submitted January 31, 2005