3.8.2 Surface Protection
Every effort should be made to cover bare ground after disturbance by construction or maintenance activities. A stand of good quality vegetation is the best long-term solution to potential erosion. The use of mulches or compost can be used on gentle slopes (1:4 V:H) orflatter. Temporary erosion control material may be necessary depending on soil type as slopes increase. These two primary considerations, soil type and slope, determine the selection of the appropriate temporary erosion control measure. Highly erodible channel areas may require more permanent channel liners or possibly riprap.
- Soils with higher percentages of fine sand or silt particles are increasingly more erosive, while soils with minimal percentages of sand or clay particles are considered cohesive soils or clays.
- As the degree of slope increases, the potential for sheet erosion increases.
- The includes approved products for hydro mulch, roll products and hydraulically applied (spray-on) products for temporary erosion control, and temporary and permanent channel protection.
- Products are approved based on soil types and for slopes for temporary erosion control and shear stress for channel protection products.
3.8.2.1 Compost or Mulch
The primary function of mulch is to maintain moisture in the soil and foster seed germination and plant development. Coordinate preferences for use of compost and mulch with each specific District. There are three types of mulch used for erosion control:
- Straw and hay mulch:Straw and hay mulch are used as surface covers in conjunction with some type of tacking agent (tackifier). The tackifier helps form a uniform mat and prevents migration of the material down the hill. Straw can also be crimped to help prevent material loss or migration. Refer to the and on the for additional information.
- Hydromulch:Hydromulches are hydraulically applied. Cellulose mulches may be applied with the seed mix and a tacking agent to form a more consolidated mat on the surface. TxDOT maintains a list of approved cellulose mulch materials. Depending on the soil type and side slope, hydraulically applied mulches have varying rates of application. Refer to the on the for additional information. TxDOT maintains an approved list for cellulose fiber mulches at .
- Compost:Compost may be blended to make compost manufactured topsoil in flat areas. Slopes up to 1V:3H should utilize Erosion Control Compost. Erosion Control Compost may be pneumatically applied on slopes 1V:3H or flatter. This material not only provides short term erosion control with mulch chips but also works to improve the existing soil. Refer to the on the for additional information.