Water Quality and Watershed Management

What is a Watershed?

A watershed is an area of land where rainwater collects and flows downhill to a common point. Drop by drop, water is channeled into soils, streams, groundwater, and eventually to the ocean. The water that is percolated underground replenishes aquifers and is then pumped into our homes for our daily needs like bathing, washing, etc.

Rainwater that doesn’t soak into the ground becomes surface runoff that flows downhill, following the natural slopes of the land until it reaches the ocean. Runoff flows through forests, farms, streams and streets, picking up whatever is in its path on the way to the ocean.

You live in a watershed!

Saipan has 11 major watersheds, all of which eventually drain to the sea. Use the map to identify which watershed you live.

Pollution on Land Threatens the Ocean

When water flows over land and into the ocean, it carries with it any dirt, trash, animal waste, oil, or other pollutants it encounters along the way.

Common pollutants found in storm water runoff include: 

  • Oil and grease from automobile and kitchen wastes
  • Sediment from unpaved roads, construction sites, and burning.
  • Nitrogen and phosphorus from fertilizer
  • Bacteria from pet waste and sewer overflows and illicit connections
  • Metals (lead, nickel, copper) from automobiles
  • Pesticides from lawns

Land based sources of pollution are a threat to human health, water quality, and the coral reef ecosystem. The BECQ Water Quality Surveillance branch regularly collects water samples and provides updates about water quality and safety.

In the CNMI, our watersheds are subject to severe erosion during rain storms and typhoons. This intense rainfall damages unpaved roads, making them impassable and dangerous, and at the same time, deposits sediment on adjacent reefs. Upland burning and clearing for the purposes of development, farming, and hunting also causes increased levels of sediments in the water. These sediments reduce the quality of water for fish and coral reefs. Uncontrolled storm water runoff (water that is not infiltrated into the ground) drains off roads, driveways and parking lots, and negatively impacts our water resources. When water runs off these types of impervious surfaces, it picks up pollutants along the way and takes them all the way to the ocean.

Priority Watersheds

A key part of the CNMI Local Action Strategy and Management Priorities is the identification of three priority watersheds to be the central focus of the CRI’s land-based coral conservation efforts. There are two priority watersheds on Saipan: Garapan (West Takpochao) and Laolao Bay, and one priority watershed on Rota: Talakhaya. These watersheds were selected for their economic, biological and social significance because they are high use areas with vital natural resources. See the following pages (or the use the links above) to learn more about the watershed management projects in each priority area.


Protecting our Watersheds

Schools, civic organizations, individuals can help to protect our watersheds, thereby helping to protect our drinking water and ocean resources for fish and coral reefs. We can all help by:

  1. Maintaining vegetation. Trees and plants slow down runoff and create opportunities for water to infiltrate soils which reduces erosion, stores water for gradual re-release, and helps control flooding.
  2. Using fertilizers, pesticides, and herbicides properly. Excessive use of these chemicals can enter into the groundwater or ocean, which then stimulates algae growth which blocks sunlight and prevents an adequate supply of oxygen to fish in the ocean. Watch the weather forecast and avoid applying fertilizers prior to a rain event. Your money and the fertilizer will go down the drain.
  3. Redirecting down spouts to water catchments. The water collected can be used for lawn or garden watering, car washing and even showers and toilets.
  4. Ensuring proper waste disposal. Locate dumpsters away from drain inlets and ensure each bin is securely covered. Hazardous waste, oil and grease should never be thrown in a garbage bin.

Follow this link to our Watershed Factsheet to learn more! 

Watershed Working Group
The Watershed Working Group is a partnership between local and federal government agencies, environmental non-profits and other concerned groups that gather to provide technical expertise and project support on watershed initiatives in the CNMI. The group meets quarterly to discuss ongoing projects and request review or recommendations on specific issues. This group has been instrumental in reviewing and contributing to the Conservation Action Plans and other guiding watershed documents.

The Watershed Working Group typically meets on the third Wednesday of the month at 8:30am quarterly. Meeting notes and presentations are posted here. If you are interested in learning more about the WWG or joining our next meeting, please contact our Watershed Coordinator, Katie Graziano at BECQ, 664-8531.