Erosion and Sedimentation Control Permits are issued by the Guam Environmental Protection Agency. They are often a condition Clearing and Grading Permit that the Department of Public Works issues. Since Clearing and Grading Permits Require GEPA review for compliance with the Guam Soil and Sedimentation Control Regulations, GEPA actually assumes the lead review and approval responsibility. For most Clearing and/or grading permits there must be an accompanying Erosion Control Plan (ECP) to protect water quality of the closet body of water, fresh or marine. Erosion Control Plans are a requirement of most land grading and clearing permits issued by the Building Official, Department of Public Works. Such a plan must accompany the permit application and must be prepared in compliance with the promulgated Soil Erosion and Sedimentation Control Regulations.

Preparing and implementing an Erosion Control Plan is generally the responsibility of the contractor, who must use accepted erosion control methods to hold soil on-site during the construction period. In some cases, especially during the wet season, special erosion control and sedimentation control measures must be taken to prevent environmental problems. An Erosion Control Plan is usually prepared an integral part of the Environmental Protection Plan (EPP). However, it may be developed as a separate or supporting document. With large projects, like subdivisions or projects on a sloping terrain, the Erosion Control Plan becomes the focal point of the EPP. Review and approval of an Erosion Control Plan by GEPA can take one week or longer, depending on the complexity of the project and completeness of the Plan upon submittal.

The 2006, the CNMI and Guam Stormwater Management Manual (Stormwater Management Manual) was developed to assist the local engineering and development communities and local government agencies in developing and implementing stormwater and erosion control plans that adequately address nonpoint source pollution through the use of currently accepted best management practices (BMPs). Guam formally adopted the Stormwater Management Manual under Executive Order 2012-02 in January, 2012.This manual was generally intended to update and replace previous reference manuals in CNMI and Guam, most notably the Guam Storm Drainage Manual (U.S. Army Corps, 1980), Stormwater Control Handbook (Soil and Water Conservation Districts of CNMI, 1989), and the Erosion and Sediment Control Manual (GEPA, 2000). Unfortunately, the sheer volume of material and diversity of topics of the prior materials make it impossible to completely replace these reference materials. Designers, regulators and the regulated community will still need to rely on prior publications for reference to the following topics:

-General Hydrology

-Drainage Design/Pipe Sizing

-Floodplain Management

-Design Specifications for Erosion and

-Sediment Control Practices

In collaboration with the Bureau of Statistics and Plans, The Guam Environmental Protection Agency, and The Department of Public Works,  the USACE developed the Guam Stormwater Manual Update and Storm Drainage Runoff Calculation Tool in 2024. This update and tool are intended to simplify the process of performing multiple calculations. These include pre development and post development calculators for:

-Runoff Curve Number

-Time Of Concentration And Travel Time

-Tr 55 Peak Runoff Calculation (Graphical Method)

-Runoff Volumes Using Manual Rainfall

-Simplified Infiltration Basin Design From GEPA

-Swale Design

-Bio-Remediation Measures

-Sand Filter

Below is the Guam Stormwater Management Manual Update that should be used in conjunction with the Storm Drainage Calculation Tool that can be downloaded below

Storm Drainage Runoff Calculation Tool Part A

Storm Drainage Runoff Calculation Tool Part B

NRCS Web Soil Survey Map

Authority:

Executive Order 2012-2

“Water Pollution Control Act” Title 10, Chapter 47, Guam Code Annotated

“Soil Erosion and Sedimentation Control” Regulations, 1985.

Regulations

Title 22, Chapter 7 (Guam Water Resource Development and Operating Regulations), Chapter 8 (Guam Sewer Connection Regulations)

Title 22, Chapter 10 (Guam Soil Erosion and Sediment Control Regulations), 

Title 22, Chapter 12 (Guam Individual Wastewater Disposal System Regulations)

Chapter 11 (Guam Water and Wastewater Operator Certification Regulations)