Division of Spill Prevention and Response


Tactic TR-1: Draining and Dewatering

Flooded tundra soils are generally anoxic (lacking oxygen) because the soil pore spaces are full of water. Use draining and dewatering to aerate the soil by lowering the water table and promoting the infiltration of oxygen (Fig. 69). Aeration enhances the ability of soil microbes to degrade residual hydrocarbons (Tactic TR-5). Use this tactic after spill residuals have been removed to the chosen extent.


Figure 69. Vacuum truck dewatering site

Drain the site by blocking incoming water with land barriers (Tactic CR-5) and pumping water from the area (Tactic CR-4). Use or enhance topographical relief to create collecting points for pumps or vacuum trucks. Trenches or sumps (Tactic CR-6) may also be needed.

Draining is not recommended when floating product is present; product may be introduced into soil pore spaces or contact vegetation when water level is drawn down. It will usually be unnecessary and impractical to drain aquatic tundra, except for small water bodies. Do not completely dewater tundra if the technique will result in contaminants contacting sediments.

Place suction hoses in all low areas where water collects (Fig. 70); suction may be required at numerous locations within a site. If the site cannot be reached by vacuum truck and hose, all-terrain vehicles (ATVs) may be used to bring in small tanks or drums to collect the water (appropriate tundra travel permits required). It may be necessary to test the collected water for contamination before draining. Proper approvals must be obtained for discharge or disposal of contaminated water from spill sites.


Figure 70. Natural low spot used for dewatering

Considerations and Limitations

  • Test water for contamination and consider disposal options and required approvals before using this tactic.
  • Tundra must be thawed to dewater soil pore spaces.
  • Equipment, Materials, and Personnel

    • Water truck (optional) (1 operator).
    • Pumps (1 operator).
    • Hoses (1 to 2 operators) – common sizes are 2- and 3-inch diameter.
    • Land barriers (Tactic CR-5).

    Updated: 12/20/2010