Tetra Tech designed and developed the MOSES-MP software which determines whether spills of mineral oil from electrical equipment are likely to reach nearby surface water via overland flow (MOSES) or to infiltrate through the subsurface to underlying groundwater (MP). The MOSES software includes the SPCC Wizard to make it easier for users to identify information needed for an SPCC Plan, which is then automatically transferred, if requested, into a customizable SPCC Plan template. This template meets the requirements of the Oil Pollution Prevention, Spill Prevention, Control, and Countermeasure (SPCC) Rule (40 CFR Part 112 Final Rule - November 13, 2009).

The MP model simulates the infiltration of mineral oil or fuels from the ground surface through soil to the groundwater table for four scenarios: a short-duration spill, a slow leak, a catastrophic spill and pre-existing soil contamination. Plots of the oil and water distribution in the subsurface are provided, as well as travel time to reach the water table.

MOSES software also has the following capabilities:

• Calculates the probability of spills from substations reaching surface waters or infiltrating to groundwater

• Calculates volumes of oil retained onsite or on land or that reaches waterbody or that is consumed by fire

• Provides a series of plots depicting the volumes of oil spilled, retained on land, or that reach a waterbody; and travel times on dry days, rainy days, or all days

• Includes a database of typical mineral oil and fuel properties.

In 2012, MOSES-MP was upgraded to the Windows 7 operating system and several processes were enhanced including transport across steep slopes, adding a more detailed simulation of fires at substations, and allowing users to track the oil and water throughout a spill. In 2020, MOSES-MP was updated for Windows 10.