for Guam's Non-Point Source Pollution Management Plan
About the Program
Monitoring is a critical component of any restoration or protection effort. Monitoring assesses over time the success of management measures in reducing pollution loads and improving water quality. To be effective, non-point source monitoring should include a combination of chemical, physical and biological components. The Water Monitoring Strategy for the Territory of Guam relies on a variety of approaches in conducting its monitoring and assessments. The most common approach is to measure the chemical and physical constituents in the water itself. The concentrations of these constituents are then compared to appropriate standards within the Guam Water Quality Standards (WQS) to determine if the designated uses of the waterbody are supported.
The Water Monitoring Strategy for the Territory of Guam (WMSTG) was originally implemented in 1978. It includes the Surface Water Monitoring Network (SWMN) and the Recreational Beach Monitoring Strategy. The goals of the WMSTG are to:
SWMN focuses mainly on the southern region of Guam, where the majority of all surface water features exist. The coastal assessment of Guam is also covered under the SWMS as the Marine and Reef Flat Networks. These two networks are incorporated into one overall network from headwaters to receiving waters, by watershed, to profile the dispersion of pollutants.
The Recreational Beach Monitoring Strategy focuses on the monitoring of "whole-body" (Primary-Use) and "limited whole body" (Secondary-Use) recreational marine waters for the presence of microbiological organisms. This program is important in that consistent monitoring ensures the protection of the public from diseases such as gastroenteritis, hepatitis and cholera caused by elevated levels of microbiological organisms.
The WMSTG is currently directed mainly at the systematic collection of physical and chemical data from fixed locations island-wide. Data is collected from both the fresh water and marine environments. It is designed to compare collected data against the Guam WQS. This is to insure that the quality of Guam's waters remains high, and suitable for their intended uses. This data is also analyzed for trends in water quality to identify possible sources of pollution and assess the effectiveness of present management practices.
The current WMSTG consists of three major water categories, river, marine and reef complexes, that are sampled based on the Rotating Basin Design, as outlined by U.S. EPA’s Environmental Monitoring and Assessment Program. Within these complexes, there are a total of 65 River Stations, 17 Reef Stations and 38 Marine Stations (see Guam EPA Monitoring Station Maps). The sampling frequencies for these stations are scheduled so four sub-complexes are sampled for two, six week periods every other year. There are also 19 Biological Stations that will be discussed in the biological monitoring section below. The first six week sampling period occurs during the dry season, January to June, with the second period during the wet season, July to December. Over a two year period, all Guam EPA sampling complexes should be monitored. This schedule allows the monitoring staff to evaluate the data from sub-complexes for possible contamination trends over a given amount of time.
The Recreational Beach Monitoring Strategy focuses on the monitoring of "whole-body" (Primary-Use) and "limited whole body" (Secondary-Use) recreational marine waters for the presence of microbiological organisms. This program is important in that consistent monitoring ensures the protection of the public from diseases such as gastroenteritis, hepatitis and cholera caused by elevated levels of microbiological organisms. Guam EPA has identified thirty-eight (38) recreational marine beaches that are sampled once a week year round, based on proximity to potential pollution sources and the intensity of use by the public (see Guam EPA Monitoring Station Maps). This results in a total of approximately one thousand nine hundred seventy six (1,976) recreational marine beach samples collected and analyzed using the USEPA approved enterococcus indicator per given year.
Physical/chemical monitoring is based on data collected for freshwater and marine water samples in the categories described as "conventionals." Guam EPA has collected extensive physical/chemical data at established sites during the early 1980s and utilizes this data set as ambient characteristics for that specific waterbody.
The following analytical parameters are classified by Guam EPA as "conventionals": pH, Total Suspended Solids, Total Dissolved Solids, Temperature, Turbidity, Nitrite-nitrogen, Dissolved oxygen, Salinity, Nitrate-nitrogen, Total phosphorous, Ortho-phosphorous. According to USEPA guidance, Guam EPA’s Physical/Chemical data set is considered as "moderate/high quality," based on technical components and spatial and temporal coverages of the current Monitoring Strategy.
Guam’s surface and marine waters have multiple assigned "Designated Uses," ranging from aquatic life protection (preservation, propagation, survival and maintenance), primary (whole body) and secondary (limited) recreational contact, and drinking water (freshwater only).
The following table summarizes the "Designated Uses" classification system and the Use Support criteria.
Table 1. Guam’s Water Classification and Designated Uses System.
While chemical water sampling provides a snapshot of conditions at the time of sample collection, biological, sediment and tissue results provide a view of conditions over a somewhat longer time period. Based upon this, the Revised Guam NPS monitoring program will serve to assess the effectiveness of agricultural and urban management measures that are currently being implemented island wide. Guam’s NPS monitoring program and the Guam Water Monitoring Strategy (GWMS) are currently being revised to incorporate new elements to its Biological Monitoring Program.
The original "Marine Biological Monitoring" was designed to only collect data on species composition, substrate type, percent cover, and fish assemblage. This program is being expanded to now include a "Toxic Materials Monitoring Program for Sediment and Tissue," and a "Freshwater Periphyton and Benthic Macroinvertebrates Assessment Program."
The Freshwater Periphyton and Benthic Macroinvertebrates Assessment Program for Guam’s river are being developed and drafted from techniques modified from USEPA guidance’s (EPA 841-D-97-022) and the 18th Edition Standard Methods. The goals of this program are to qualitatively and quantitatively assess the periphyton and benthic macroinvertebrate assemblages in Guam’s freshwater environments with water quality during the wet and dry seasons. Draft Documents will not be finalized until all metrics are tested and verified and all supporting documents (i.e., Sampling Analyses Plan [SAP], Stand Operating Procedures [SOP], Data Quality Objectives [DQO], and a Quality Assurance Program Plan [QAPP]) are also developed and finalized. The projected time frame for document completion and metric verification is the end of fiscal year 2002.
The second proposed component to be added the current Biological Monitoring Program is a "Toxic Materials Monitoring Program." This program is being designed to assess the levels of the major chemicals of potential environmental concern (CPEC) in both sediment and the tissue of important recreational, commercial and subsistence target species, in and around the island of Guam. The data generated from this program will be used to establish the first "Consumption Advisories" for the island of Guam. The projected time frame for document completion, CPEC selection and target species list is the end of fiscal year 2001.
To help facilitate the data management, storage and analyses of all monitoring data, a laboratory information management system (LIMS) and a geographic information system (GIS) were purchased with the grant funds. All corresponding software and hardware have been purchased and assembled. Training was initially going to be provided by in-house staff, but due to the recent unforeseen reductions in Agency staff, that training did not occur. Training for these systems has been given the highest priority by the Agency in upcoming fiscal year. Both systems are expected to be fully operation by the end of fiscal year 2001.
The sites below contain additional information about Monitoring Program issues (pages will open in a new browser window).
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