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The Sanitary Landfill 325
and embankments. Chain link, barbed wire added to chain link, and open farm-type fencing are
examples of appropriate fencing. Access to facilities should be controlled through gates that can be
locked when the site is unsupervised.

10.4.20 CONTROL OF RUN-ON AND RUNOFF

The landfill operator is required to prevent run-on onto the active portion of the landfill and to col-
lect runoff as well (40 CFR Part 258.26). Run-on and runoff control systems must be designed
based on the volume of water anticipated from a 24-h, 25-year storm. The purpose of a run-on con-
trol system is to collect and redirect surface waters to minimize the amount of water entering land-
fill cells. As discussed below, minimizing the volume of water entering a landfill will limit the
volume of leachate generated. Run-on control is accomplished by constructing berms and swales
up-gradient of the fill area in order to redirect water to stormwater control structures.
If stormwater enters the landfill unit and contacts waste, the stormwater, according to regula-
tions, becomes leachate and must be managed as leachate. Such leachate generation will increase
costs and can overload leachate treatment systems.
Runoff control systems must collect and handle runoff from the active portion of the landfill,
including areas that contact MSW. Runoff control can be accomplished through stormwater con-
veyance structures that divert runoff and leachate to a storage system for eventual treatment. Other
structures used for run-on and runoff controls include seepage ditches, seepage basins, and sedimen-
tation basins (Figures 10.19 and 10.20). U.S. EPA (1985) discusses each of these structures in detail.
After a landfill unit has been sealed with a final cover, stormwater runoff is managed as
stormwater and not leachate. Therefore, waters running off the final cover system of closed areas
may not require treatment and can be combined with run-on waters. Run-on and runoff must be
managed in accordance with the discharge requirements of the Clean Water Act including the
National Pollutant Discharge Elimination System (NPDES) (U.S. EPA, 1994).

10.4.21 MANAGEMENT OF SURFACE WATER

MSWLFs are required to prevent any discharge of pollutants into surface water, including wetlands
(40 CFR Part 258.27). The facility should determine if it is in conformance with requirements of
the Clean Water Act and the NPDES requirements under the Clean Water Act. The EPA and
approved states have jurisdiction over discharge of pollutants into U.S. waters including wetlands.
Landfills discharging pollutants into the U.S. waters require a Section 402 (NPDES) permit.
Landfill units that have a point source discharge must have a NPDES permit. Point source dis-
charges from landfills include:

● The release of leachate from a leachate collection or on-site treatment system into water
● Disposal of solid waste into water

Run-off control formed
by waste slope Run-on control
and containment ditch(grass
sideslope or stone lined)
Waste

Liner

FIGURE 10.19 Schematic of run-on and runoff controls at a landfill (Reproduced with kind permission of
MACTEC Engineering and Consulting, Inc., formerly known as ABB Environmental Services).