Restoring Montgomery County’s Streams · Overlapping stones help protect stream banks from...

Brush LayeringLayers of live branch cuttings are installed horizontally. These cutting will sprout newplants which will then stabilize eroded streambank slopes.

Root WadsTree trunks with attached roots are anchored in streambanks to provide cover for fish, amphibians, and aquaticinsects. The sinuous root mass slows the flow of thestream, armors the bank, deflects energy away from the bank, and forms scour pools, providing greater habitat benefits.

Our stream restorationprogram uses a variety oftechniques to stabilizestream banks, reestablishaquatic habitat, and prevent erosion and sediment pollution to ourstreams and watersheds.Restoration efforts generallyemploy natural materials such asrocks, logs, and native vegetation toreduce pressure on eroded banks andprevent down-cutting of the streambed, in addition to stream bufferreforestation efforts, which providelong-term protection.

In areas with wide buffers, wherethe stream is farther away from property lines, “softer” techniquesand natural materials are used, which often help restorethe meander pattern found in stablestreams. Urbanizedareas, with development closerto the stream, mayrequire “harder” engineered solutions.

Armored Sewer Crossing

Stone Toe ProtectionStone installed at the base of the stream bank protects it from heavier storm flows and prevents undermining. The stream banksare graded back and planted with native vegetation for additional stabilization anderosion protection.

Rock Pack and Flush CutStream bank trees seriously undercut by erosive storm flows can be protected withsupportive rock packing. If undercut too far,they can be “flush cut,” which allows theroots to remain in the bank for stabilizationand erosion protection.

J HookRock is placed in streams in the shape of a “J” to channel the flow of water away fromeroding stream banks. The “hook” or curvedtip of the “J” has slots which allow fast-flowing water through to dissipate energyand form scour pools, which add habitat.

Cross VaneStone is carefully positioned at an angle tocreate a “vane” which diverts the flow ofwater toward the center of the stream, thereby protecting stream banks, maintainingstream bed elevation, and preventing furtherstream downcutting.

Shallow WetlandsCreation of a shallow wetland below a localstormdrain allows water quality treatmentthrough infiltration, nutrient uptake, and limited detention. Shallow wetlands also provide habitat for balanced aquatic plantand animal communities.

Coir LogsMade from biodegradable coconut fibers,they provide a medium for vegetation, protecting less erosive stream reaches by holding the bank in place and catching eroding material.

Imbricated Rip Rap Overlapping stones help protect stream banks fromerosion or potential failure. Typically used alongstream reaches where eroding stream banks threatenprivate property or public infrastructure, or where thestream is highly confined and subject to particularlyerosive storm flows.

Log VaneLogs are placed and anchored to divert stream flowaway from eroding stream banks towards the centerof the stream. The concentrated stream current formsscour pools below the vane, adding pool habitat.Vanes can also be constructed with rock.

Step PoolsUsed downstream in areas where rock—often addedto protect a sewer crossing—has raised the level ofthe stream, or in other areas where the stream dropssteeply. Step pools allow stream flow to lose erosiveenergy by gradually lowering the elevation of astream in a series of steps.

Department ofEnvironmental

Protection

Montgomery CountyMaryland

Restoring Montgomery County’s StreamsRestoring Montgomery County’s Streams