Development of low-water crossing design guidelines for very low ADT routes in Illinois.

PDFTech ReportFHWA-ICT-16-020ICT-16-022UILU-ENG-2016-2022R27-148Bridges and culvertsFloodsLow volume roadsStructural designUnited StatesIllinoisIllinois Center for TransportationBhattarai, RabinKalita, PrasantaGautam, SudipHoward, HeidiSvendsen, NielsGambill, DanielIllinois Center for TransportationIllinois. Dept. of Transportation. Bureau of Materials and Physical ResearchUnited States. Federal Highway AdministrationUS Transportation CollectionThe Illinois Department of Transportation (IDOT) and local agencies monitor and regulate the 146,764 mi of roadway that areopen to public travel in the State of Illinois. There are many old and aging bridges, culverts, and low-water crossings on rural low-volumeroads that need to be replaced. Low-water crossings (LWCs) have been used as an economical alternative to culverts andbridges, designed without overtopping, on low-volume roads where there is low number of floods. The lack of design guidancehas posed difficulty for county engineers in Illinois in deciding when, where, and which type of low-water crossing to use. Theresulting structure is often either overdesigned or underdesigned. A study was conducted to design the guidelines for LWCs in Illinois at the University of Illinois at Urbana-Champaign incollaboration with the U.S. Army Corps of Engineers - Construction Engineering Research Laboratory (CERL) and support from theIDOT. The study included a literature review, an LWC survey, and case studies on LWCs in Illinois. The results from a surveyconducted among the county engineers in Illinois about their experience with LWCs are presented, along with commonly usedLWCs, site considerations, selection criteria, and signage requirements. Design criteria and procedure for the LWCs design,construction, and best management practices are also discussed. Additionally, case studies, design examples, and permittingrequirements for LWCs are included in the report. Implementation of LWC guidelines could save local agencies significantfunding, due to lower construction and maintenance costs, less channel and flood plain blockage, and better adaptability andstorm-proofing characteristics, as well as reduced impacts to aquatic organism passage