3000 SR 529 2016-01-01 MF Import

BMP C122: Nets and Blankets Purpnse lirosion control ncts and blankets are intenu�d to prevent erosion and hold seed und mulch in place on stcep slopes and in channels so that veget:uion can bccome weU eswblishcd. In addition, some nets and blankets can be uscd to pemianenUy rcinforcc turf to protcct drainage «ays during high flow•s. Ncts (commonly callcd matting) are stnnds of malcrial wovcn imo an open, but high-tensile strength net (for cxamplc, coconut fibcr matting). F3lankcts are strands of material that arc not tightly wo��cn, but insicad fomi a layer of imcdocking fibcrs, typically hcld togcthcr by a hiodegradable or photodegr.�dablc netting (for example, cxcclsior or straw• blankets). Thcy generelly ha�•c loµ�cr tcnsile strength than nets, but cover the ground morc completcly. Coir (coconut 6ber) fabric comes as both ncts and blankcts. Cnnditions ojUsc Frosion control ncts and blankets should bc uscd: . To aid pcmmnen� vcgct;ucd stabilization of slopcs'_H:I V or ercatcr and �t ith more than 10 feet of venical relief. . For drainage ditchcs and suales (highly recommended). Thc application of appropriate netting or blanket to drainage ditches and swalcs can pmtecl bare soil from channelized runofTwhile �egetation is establishcd. Nets anA blankets also can capture a great deal of sedirncnt duc to their opcn, porous swcture. Synthctic nets and blankek can bc uscd to pertnancndy stabilizc channcls and may pro��idc a cost-c(Tcctice, cm ironmcntally prcfcrablc altcmaticc to riprap. 100 percent synthetic blankets manufac�ured for usc in Jitches may� bc casily rcuscd as tcmporiry ditch lin�rs. Disadeantagcs of blankets mcludc: • Surfacc preparation requircd; . On slopcs strcper tltan ?.5: I. bl;inkrt ins�allcrs ma}' nccd to bc roprd and h:imcsscd for sa�ct��; . 1'hcy cost ,�t Icast Sa.000-6,OOJ per :ure in.ialled. Advant:igcs of hl:mkGs includc: . Can bc inslallcd withoul roobiliring spccial cyuipmenl; . Can bc installed by anyunc with minimal traii.ing; • Can bc installcd in stagts or phascs as lhc projcci prngresscs: • Sccd ;md Icrtilizcr can 6c hand•pl:recd by thc insiallcrs as �hcy progrcss do��n thc slopc; • Can bc installcd in ;my wcathcr; • Thcrc arc numcrous typcs of hlankcts that can bc dcsigncd wiih varinus paramcicrs in minJ. Thosc par�mctcrs includr. fibcr blend, mcsh strcngth, longcvily, biodcgradability, cost, and availability. 4-22 Volumc ll — Construction Stonnwafer Pollution Provention February 2005