SHEET STATE PROJECT NUMBER _ n o s n h o J . a l e g n A 4 NOTE: : te r o e N s ee 1.Check dams of fiber rolls, riprap, or gravel bags U S _ may be used as approved by the CO, to meet the functional Class 1 riprap requirements of the check dam device. Trench 2" min. 2.Repair all rills or gullies and properly compact prior to installation. 6" min. 6" 3.Install check dams in ditches perpendicular to the flowline. 12" (min.) V-ditch design shown. 4.Stake fiber rolls in place with 1⅛" x 1⅛" wood stakes. Check dam installation details are Drive stakes at each end of the fiber roll and at similar for flat-bottom ditches. 2' (max) spacing. V-DITCH CROSS SECTION CROSS SECTION 5.Drive stakes into undisturbed soil of trench bottom 16" (min). Expose stakes 2" (min.) above top of fiber roll. 6.Provide sufficient length to prevent water from flowing around the ends of the fiber roll. See Note 5 7.Adjust check dam spacing based on site-specific conditions. Place excavated material on uphill side of fiber roll Fiber roll 9" Ø min. Flow Line Class 1 riprap Flow 6'' min Trench 2" min. 6'' 16" min 12" (min.) 12'' (typ.) Gravel bag FLAT-BOTTOM DITCH FIBER ROLL CROSS SECTION CROSS SECTION STAKING DETAIL n g Curve ends upstream d RIPRAP . GRAVEL BAG to prevent flow around 3 5 CHECK DAM SPACING CHECK DAM SPACING* - the ends 7 Flow 5 See Note 6 (See Note 7) (See Note 7) 1 C \ s l CHECK DAM CHECK DAM i a DITCH DITCH t SPACING (max.) SPACING (max.) e GRADE GRADE D (ft) _ (ft) 4 1 P 2% 150 F 2% 150 \ PLAN 4 3% 100 1 3% 100 - P F 4% 80 \ 4% 80 s g 5% 60 n i 5% FIBER ROLL 60 w a 6% 50 r CHECK DAM SPACING* 6% 50 D \ T * Do not use gravel bag check dams I (See Note 7) P on ditch grades steeper than 6% D - L CHECK DAM F DITCH RIPRAP CHECK DAM C \ SPACING (max.) : GRADE GRAVEL BAG CHECK DAM N (ft) M P 2% 150 5 0 : 3% 100 U.S. DEPARTMENT OF TRANSPORTATION 6 5 FEDERAL HIGHWAY ADMINISTRATION : 4% 80 2 CENTRAL FEDERAL LANDS HIGHWAY DIVISION 1 5% 60 U.S. CUSTOMARY DETAIL * Spacing calculated based on 9" Ø min fiber roll. Do not use fiber roll check dams on ditch grades steeper than 5%. CHECK DAM 7 1 0 2 DETAIL APPROVED FOR USE 01/2011 DETAIL / 8 NO SCALE 1 FIBER ROLL CHECK DAM REVISED: 08/2014 / C157-53 9 NOTES TO THE DESIGNER Last Updated: August 2014 General Information 1. Appropriate Applications. Check dams reduce scour in a channel or ditch and provide runoff treatment by reducing flow velocity and encouraging sediment deposition. Appropriate applications include: Fiber rolls are appropriate for lower flow conditions, gravel bags and riprap check dams in higher flow conditions Steep channels where storm water runoff velocities exceed 3 ft/s During the establishment of grass linings in ditches Use in conjunction with RECP lining in ditches steeper than 5% or 6% (See CFL Detail C157-54) 2. Limitations. Not used in live streams Drainage areas 10 acres or less 3. Layout Guidance. Install the first check dam about 15 ft from the outfall and at regular intervals based on slope gradient and soil type (steeper slopes and more erosive soils (e.g. loose sand or silt) will require shorter spacing between check dams). When installing a series of check dams in a channel, install outlet stabilization measures below the final dam, such as riprap or geotextile, to minimize erosion potential. Applicable SCRs None Typical Pay Item Used We will leave it up to the Contractor to select the specific type of drop inlet protection to use on the project. Include both plan sheets and a generic pay item in the PS&E. 15706-0200 Soil erosion control, check dam [EA] If you would like to specify a type of check dam to use, show the type in parenthesis in the pay item description. For example Soil erosion control, check dam (riprap) Updates January 2011 Updated FLH Standard drawing by: Adding sediment log and gravel bag check dams August 2014 Changed spacing tables, size of fiber roll Updated for FP-14 Updated border Designer Notes for CFLHD Drawing 157-53 .