Probabilistic Surface Water Sampling Sites 2011-2015
Probabilistic Surface Water Sampling Sites 2011-2015

The Massachusetts Probabilistic Monitoring & Assessment Program (MAP2) is one component of the Massachusetts Department of Environmental Protection (MassDEP) Watershed Planning Program (WPP) water quality monitoring strategy. MAP2 uses data from randomly selected sites to generate an unbiased assessment of water quality conditions throughout the state. Initially, MAP2 is limited to non-tidal perennial wadeable streams (target population) with the expectation of expansion to other water resources (e.g., non-wadeable streams, lakes, estuaries, wetlands) when and if additional resources and funding become available in the future. MassDEP is conducting this assessment to support our efforts in protecting Massachusetts water quality and assess if our waters are meeting the goals of the Massachusetts Surface Water Quality Standards (i.e., is the water suitable for fish & other aquatic life, are bacteria levels safe for people to come into contact with the water, etc.). This page gives participating landowners a general idea of what MassDEP is sampling for and when the sampling will take place.

MAP2 was initiated in 2010 as a pilot project to test methodologies and protocols. MassDEP WPP personnel began full implementation of the program in 2011 and have continued to monitor the state on a five year cycle in conjunction with the other components of the state’s water quality monitoring strategy. As part of the MAP2 program the major basins in the state were regionally assigned to five groups with each group containing an approximately equal quantity of river miles. During each year of the five year cycle, one of these groups is monitored thus covering the entire state’s target population in a 5 year period (see figure above). This effort involves sampling at approximately 160 randomly selected sites throughout the state from 2011-2015 as shown in the figure above. In 2015, the northeast basin group (Charles, SuAsCo, Merrimack, Shawsheen, Parker, Ipswich and North Coastal Basins) will be the focus of the monitoring effort.

How to use the schedule: 
Note: The first schedule will be posted in the March/April timeframe for a given sampling year:
• Each sample site has a unique code that appears on your contact letter. The code looks like this: MAP2-402 or RSN2-183.
• Find your unique code referenced in your permission request letter in the table below to find your Sampling Group.
• Consult the calendar below to find the dates for your Sampling Group.

Surface Water Sampling Sites and Schedule for 2015

General Information about Site Visits:  
• MassDEP WPP Staff are always in state vehicles for field activities.
• Most sampling efforts are included in the calendar below.
• Two exceptions are the macroinvertebrate and fish sampling trips (one each per site) that are difficult to pre-schedule but that typically take place in the July- September timeframe.
• Most sampling efforts typically require staff to be on site for 30 minutes or fewer.
• Macroinvertebrate and Fish sampling efforts are typically 1-2 hours.
• Sampling typically occurs during daylight hours in non-winter months (May - October). Some scheduled visits may change due to unforeseen circumstances such as severe weather or vehicle/equipment failures, but the information below is the best information available as of the time of posting.

Types of Data Collected

IndicatorSampling PeriodFrequencySampling Type Classification 
(code seen on calendar)
Nutrients (nitrogen, phosphorus)May-SeptemberMonthlyWater Quality
E. coli bacteria
True Color
Aesthetic observations
Dissolved metalsJune-AugustMonthly
Dissolved oxygenJune-AugustMonthlyProbe Deploy/Pickup
Specific ConductivityJune-AugustMonthly
Macroinvertebrate CommunityJune-AugustOnceMacroinvertebrates
Fish CommunityAugust-SeptemberOnceFish Population
RBP Habitat AssessmentJuly-SeptemberTwiceMacroinvertebrate or Fish Population

Additional Resources:
For information on Probabilistic Sampling, go to EPA's web site.
See additional information on 314 CMR 4.00: Massachusetts Surface Water Quality Standards
Sample Letter for Participating Property Owners  doc format of Sample Letter for  Participating Property Owners
Examples of Sampling Sites and Schedules  doc format of Examples of Sampling Sites and Schedules