Shoreline Monitoring FAQs

Monitors receive instruction on the beach.

Find responses to Frequently Asked Questions related to the Marine Debris Monitoring and Assessment Project (MDMAP). If you have a question that’s not listed here, contact us at

Site Selection

The most important factor influencing site selection is your monitoring objective. For example, if you are interested in the debris deposited on the shoreline from a local river, consider selecting sites inside and outside of the area influenced by the river outflow to facilitate comparison. The site selection criteria listed in NOAA’s protocols should be used as a general guideline, met where possible, and assessed on a case-by-case basis.

Select your 100-meter segment based on areas with relatively low public usage, little evidence of debris from day use (picnic debris), and areas that are not immediately adjacent to an obstruction to nearshore circulation (e.g., breakwater, point of land). Also consider landmarks or permanent features to assist in returning to the same segment for future surveys.


Surveys must be conducted on a regular, every 28-day schedule. If you need to miss a survey, it should be made up within a three-day window of the original survey date (i.e., 28 days ± 3 days). That gives you a seven-day window for completing the missed survey.

The latitude/longitude units can usually be changed in the general settings of the GPS. In the general settings, look for the format for decimal degrees (DDD.DDDDD). If this is not an option, record the latitudes/longitudes in the format provided and convert to decimal degrees at a later time. Here is a suggested online tool to convert between units:

Taking photos of the entire site from the beginning and end points during each survey is a good way to visually capture changes in shoreline topography and other characteristics that may affect debris deposition. In addition, please take photos of interesting, unidentifiable, or fouled debris (organisms growing on or attached to debris). Make sure to upload survey photos to the database along with the corresponding survey data.

Shoreline Characterization

When you conduct your initial shoreline characterization, it is important to arrive at the site at low tide so that you can capture the entire width of the beach. In order to record GPS readings at the water’s edge, watch the breaking waves to try to determine the shoreward extent of the water. Record coordinates at that point. If a portion of the shoreline site is underwater at subsequent surveys do not try to enter the water to survey. Only survey the exposed area of the shoreline and always remember that your safely comes first! This includes being aware of the water and waves at all times. This is why measuring beach width at each survey is important.

Tidal distance is the horizontal dimension of the beach, measured perpendicular to the shoreline, from the average low tide line to the average high tide line. Arrive at your site at low tide and measure the distance from the water’s edge to the high tide wrack line.

Beach slope is a measure of the angle of the beach, which affects how debris is deposited on the shoreline. Although rigorous approaches to measuring beach slope exist, for the purposes of MDMAP, beach slope can be visually estimated. For your shoreline characterization, please record the slope of the beach in the foreshore or the beach face (the area between low and high tide). The beach slope may steepen or flatten seasonally and over time (e.g., large storm events may increase the slope). Please record these changes in the notes section of the shoreline characterization, and take photos of the beach cross-section.

The back of the shoreline is defined by the MDMAP as the first major change in substrate, which may include a vegetation line, cliff, or other barrier. If you are interested in also monitoring debris that may be pushed back into vegetation behind the beach during storms, that debris should be tallied on a separate data sheet so that it's not included in the calculated debris flux or concentration. Data entered into the NOAA database should only reflect the debris up to the first change in substrate. If the back of the shoreline is only a partial barrier, for example a patch of vegetation behind which there is more beach, then survey up to the first continuous barrier (include that vegetation patch and the area behind it). In some cases, shoreline sites may be too complex to clearly delineate a maximum landward limit where debris might be deposited. These types of sites, and shorelines that are very high energy or dominated by sedimentary deposits, may not be good shoreline survey candidates. For the same reason, barrier islands and other shifting substrates are not ideal survey locations.

Survey Protocols

Your line of sight should be determined based on your eyesight and survey experience, ability to detect debris, substrate grain size and color, size and abundance of natural debris, and typical abundance, size, and composition of marine debris. One meter is a good starting point. Survey partners could hold opposite ends of a rope with a ribbon or marker tied in the middle, with each surveyor assigned the area on their side of the rope as you walk parallel to each other.

Beach width is the horizontal dimension of the beach, covering the distance from the water’s edge to the back of the shoreline as defined on your Shoreline Characterization. The horizontal arrow in the below figure depicts the beach width for this shoreline.

Knowing the width of the shoreline allows NOAA to report debris densities in units of number of items per square meter of shoreline. NOAA asks for the shoreline width at each survey, ideally at low tide, in order to evaluate the variability in shoreline width over the course of the project.

If the shoreline site is irregularly shaped, you will need to measure the width in at least three different places (for a 100-meter long shoreline site) in order to get an average shoreline width. Please sketch the shape of the site in the data sheet notes section. Break the shoreline into a series of rectangles and measure the length and width of each. This does not need to be done at every survey. Please consult NOAA MDP if you have questions (

Items located beyond the first barrier can be noted and described in the notes section of the data sheet; however, these items should not be included in the tallied data for the various debris items.

If you suspect that you may have found debris with invasive species, please take clear photos of the item, attached organism, and any identifying marks on the object. Remove the item from the water or shoreline and place on dry land well above the high tide line. Please contact the appropriate Pacific region state invasive species coordinator listed at In your report, note the current location of the item.

If you encounter hazardous items such as oil or chemical drums, contact your local authorities (a 911 call), state environmental health agency, and the National Response Center (1-800-424-8802). Provide as much information as possible so the authorities can determine how to respond.

Contact your local authorities (a 911 call), state environmental health agency, and the US Coast Guard Pacific Area Command ((510)437-3701) or Atlantic Area Command ((757)398-6700). Provide as much information as possible so the authorities can determine how to respond.

If an item has unique identifiers and may be traceable to an individual or group, please take photos, report it to a local land manager (e.g., a Park Ranger), and report the item to (note that the item was found during a monitoring survey). Use your best judgment to determine what may or may not be valuable. Remember that debris from abroad washes up on our shores all the time.

Taking GPS coordinates of each transect helps NOAA to track the location of transects and to ensure that the survey site location is not changing over time (due to moving landmarks or shifting beach dynamics). Additionally, it helps to ensure that site start/end points are located correctly and that equipment is functioning properly.

Taking GPS coordinates of each transect helps NOAA to track the location of transects and to ensure that the survey site location is not changing over time (due to moving landmarks or shifting beach dynamics). Additionally, it helps to ensure that site start/end points are located correctly and that equipment is functioning properly.

Recording Debris Items

If you don’t know whether an item is rubber, plastic, metal, etc., record it under “Other/Unclassifiable,” provide a description, and take photos. If an item is made of multiple material types, record it according to the most prevalent material type on the exposed surface of the item.

Record the item in the condition you found it. If the item was broken when you found it, record each piece separately. If it broke while you were examining it, record the debris as one item only.

Be very careful and do not attempt to pull large items out of the sand if it may be dangerous to do so. When recording the item in the “large debris” section, note the dimensions of the visible portion of the item, take a photo, and make a note that only a portion of the item was measured.

Items should be recorded according to how they’re found at the time of the survey. For example, if a circular strap or band is found enclosed and is < 30 cm in all dimensions it should be recorded as a regular-sized item, but if it is opened/detached and is longer than 30 cm, it should be recorded as a large item.

Smaller (meso- and micro-size) debris is hazardous to marine life and in some instances may be more abundant than larger debris. However, the 2.5 cm size cutoff (about the size of a bottle cap) is used as a standard metric because it is the smallest size that can reliably and consistently be detected with the human eye. Having this size standard increases the reliability of the data being collected, providing a more accurate picture and more robust results. Feel free to record comments or counts of small debris in the “notes” section of the datasheet. Other methods exist for evaluating smaller debris (e.g., sieve samples). For more information, see section 2.8 of Marine Debris Monitoring and Assessment: Recommendations for Monitoring Debris Trends in the Marine Environment.

Search the Monitoring Photo Gallery in the MDMAP “Get Started” Toolbox for the item in question. If you think the item might be a fragment, see the FAQ "Should I record an item as a “fragment” of a given material type, or under the “other” category?"

A fragment is a piece of a larger item that can no longer be identified, or that represents less than 50% the size of the original item. An “other” item would be something that is identifiable but not listed on the datasheet, for example a metal car part. It’s helpful to comment in the notes section of the datasheet on what types of “other” items are found at your survey site.

No. Natural woody debris does not fall under the official definition of marine debris. Only processed or treated lumber should be recorded. Wood that has been cut into beams or planks and/or treated should be recorded as lumber/building material. Burnt firewood is not considered marine debris unless it is clearly processed lumber.

Items should be recorded according to the primary material type on the surface of the item.

Balloons can be made of either rubber or plastic. Plastic (Mylar) balloons have a seam and are made of a metal (foil) coated plastic such as polyethylene or nylon. They usually have a shiny, reflective surface and often times have designs with pictures and/or words. Latex balloons are the traditional ‘party’ balloons. They are also often used at festivals, open houses, sales, mass balloon releases, etc. These balloons are made of natural or synthetic latex, are usually round or oval in shape, and can come in a variety of colors. *Note: The Rubber "Balloons ‐ Latex" debris field was added to datasheet Version 2.0 (March 2016). Search the Monitoring Photo Gallery in the MDMAP “Get Started” Toolbox for photos of both types of balloons.

Data Entry and Submissions

Please enter data into MDMAP as soon as possible after each survey to ensure that data is entered accurately.

If possible, please retain the paper data sheets until the end of the project. Alternatively, you can mail them to NOAA at the following address:

NOAA Marine Debris Program
Attn: Shoreline Survey Datasheets
N/ORR, SSMC4, Rm 10234
1305 East West Highway
Silver Spring, Maryland 20910

NOAA will share the results of any staff or partner data analysis efforts as soon as they are available. Information will be shared through email updates to MDMAP participants and on our blog.