806.7 Other Divisions' Activities
806.7.1 Maintenance Activities
Maintenance activities that involve land disturbance (destruction of the root zone) of one acre or more can be accomplished under the provisions of MoDOT’s land disturbance permit that has been issued by MDNR. The same types of best management practices (BMPs) used for roadside development and described within the MoDOT Storm Water Pollution Prevention Plan (SWPPP) can be used to effectively reduce the off-site movement of soil particles from maintenance activities.
It is important to note that regardless of the size of the land disturbance operation, whether equal to or more or less than an acre, precautions must be taken to ensure that erosion and sediment delivery off of MoDOT’s right of way or into waters of the state does not occur. Waters of the state could include rivers, lakes, ponds, streams, wetlands, etc.
For contract construction projects, all erosion and/or sediment control BMPs are typically removed by the contractor after vegetation has been established. If any maintenance or removal of BMPs is necessary after final project acceptance, MoDOT Construction personnel should coordinate those activities with Maintenance personnel. In some instances, it may be beneficial to leave rock ditch checks in place for a longer period of time to dissipate the energy of the runoff in the ditch until a good root system has developed. Once permanent vegetation has been established, BMPs can be removed. Rock ditch checks may be graded out and blended into the slopes and bottom of ditches for permanent erosion control. Biodegradable BMPs, such as mulch or compost berms, may be left in place or leveled and left in place to break down naturally over time.
From an erosion and sediment control standpoint removal of trees, brush and grass by grubbing or mowing, for aesthetic purposes, is inadvisable.
806.7.2 Traffic Activities (Permits)
MoDOT is the holder of a State Operating Permit (issued under the provisions of the National Pollutant Discharge Elimination System - NPDES) for work that is performed on MoDOT right of way by MoDOT or its contractors. However, MoDOT’s permit does not authorize work by private developers or other public or private entities that perform limited work on MoDOT right of way as part of a larger project. If a non-MoDOT project will involve disturbance of 1 acre or more of ground surface, then the developer will be required to obtain an NPDES permit from MDNR. Before MoDOT issues an entry or access permit to perform work on MoDOT right of way, the developer must provide proof that they have obtained the appropriate permit from MDNR, or some type of proof that the activity is exempt from MDNR’s NPDES requirements.
806.7.3 Materials Activities
The district geologist, working with the project development team will determine the steepness of the back slopes and the fill slopes based on the soils and geology of the area. Erosion and subsequent water pollution can be an issue when sediment from eroding back slopes and fill slopes is not captured in the ditch at the toe of the fill. In situations where steepness of slopes or undesirable soils and geology leads to the inability to achieve a desirable stand of permanent vegetation, permanent features on the slope, or in the ditch down grade from the fill, are to be installed.