FLOOD03332

• County: Statewide
• Community: State of Colorado
• Basin: Statewide
• Title: Bank Erosion/Self-Help Brochure
• Date: 4/19/1984
• Prepared For: State of Colorado
• Floodplain - Doc Type: Educational/Technical/Reference Information

DISADVANTAGES: 1)

Stabl I Ity of rlprap blanket is hard to accompl Ish.

2)

Materials may be hard to obtain.

3)

Heavy equipment required for constructIon.

4)

Difficult to construct where access Is limited.

5)

Moderately high Initial costs.

COSTS:.!! In-place costs of a rlprap blanket
and transportation of stone are $23/cubic
bank-foot, total cost would equate to $35 per

including
yard.:Y
bank-foot

bank preparation, bedding material
Assuming 1-1/2 cubic yards per
of protection.

MAINTENAI'K;E REQUIREMENTS: This structure is subject to displacement. The effectiveness
of the structure will be Impaired by thinning of the protective layer or settling of the
structure. Restorat Ion of the rock 5 lope protect ion to the des i goad top el evat lon,
equivalent thickness, and reduction of voids in the facing should be accomplished when
needed.

ENVIRONMENTAL ASPECT: No special equipment or construction practices are necessary for
riprap protection. This aspect lessens the impacts associated with construction on the
riverine ecosystem. The rock structure, although difficult to walk on, takes on a natural
appearance, and is acceptable in recreational areas. If rlprap is exposed to freshwater,
vegetation wi I I often grow through rocks, adding structural value to the bank material and
restoring plants which can be used by wildlife. Rlprap in an aquatic environment allows
for attachment sites for organisms providing a food source and habitat for fish. A
negative aspect of riprap is the extensive bank reshapIng sometimes associated with its
placement. Remova I of vegetat Ion In preparat ion for r I prapp i ng can destroy nat I ve plants
and wildlife habitat and take on a channelized appearance which may not be aesthetically
pleasing. Manual placement of rlprap may prove to be less environmentally damaging and
give the protected area a nore natural appearance. Vegetation should be allowed to grow
through the riprap. Riprap blankets appear to be the most suitable type of bank structure
for m::::>st locations from an overall vIewpoint that takes cost-effectiveness and
environmental Impacts, as well as degree of protection, into account.

-11 Estimated costs Included In this brochure assume protection of a 12-foot high
streambank.

Y Costs shown are $23 per cub I c yard. Depend i ng on construct ion methods, actua I cost
may vary by plus or minus 20 percent of values presented in this brochure.

12