Information about Submitting Water Quality Data for Maryland’s Integrated Report



Informational Public Meeting Announcement for the Draft 2024 Integrated Report (IR) of Surface Water Quality

The Maryland Department of the Environment (MDE) is pleased to announce the availability of the Draft 2024 IR for public review and comment.  The 2024 IR includes the 303(d) 2025-2032 Vision, which provides a long-term vision for assessment, restoration, and protection under the Clean Water Act Section 303(d). 

The public review and comment period for both the IR and the 2025-2032 Vision will run from May 31, 2024-July 1, 2024.  The 2024 Draft IR is posted on MDE's website here

The Department is hosting a virtual information public meeting for both the IR and the 2025-2032 Vision at 6 pm on Thursday, June 13, 2024.  

Virtual 2024 IR Public Meeting
Thursday, June 13 · 6:00 – 8:00pm
Time zone: America/New_York
Google Meet joining info
Video call link:
Or dial: ‪(US) +1 209-850-2368‬ PIN: ‪383 350 004‬#
More phone numbers:

Please contact Becky Monahan at​ or (410)537-3947 with any questions. 

Partnership with the Chesapeake Monitoring Cooperative

MDE is pleased to announce that we are partnering with the Chesapeake Monitoring Cooperative (CMC) to obtain non-governmental organization (NGO) and citizen data for assessing water quality for the Integrated Report of Surface Water Quality. 

The CMC's goal is to connect initiatives across monitoring groups and regions. They provide technical, programmatic, and outreach support in order to integrate volunteer-based water quality and macroinvertebrate monitoring data into a centralized data hub, the Chesapeake Data Explorer. These data are publicly available and used to assess the health of the Chesapeake Bay and watershed.
MDE is striving to incorporate more NGO and citizen data into the Integrated Report.  Partnering with the CMC will allow us to reach more groups by sharing the workload of evaluating data quality,  quality assurance/quality control (QA/QC) of datasets, organizing, and storing data with the CMC.  The partnership will also provide our data submitters with support and guidance from the CMC and the ease of loading data into one centralized database.  
MDE encourages all NGO groups interested in submitting data for the IR, to do so through the CMC's program and the Chesapeake Data Explorer.  MDE and the CMC will be working together to assist groups in this transition.  MDE plans to download data from the CMC's Chesapeake Data Explorer for use in the Integrated Report.  
For more information on the Chesapeake Monitoring Cooperative, please see their website here:​


As part of the federal Clean Water Act, MDE submits a biennial Integrated Report (IR) to the Environmental Protection Agency (EPA) that provides information on both impaired and non-impaired waters within the State of Maryland. In order to provide the most comprehensive report, the Department relies on water quality data from a variety of sources including Federal and State agencies, local government agencies, researchers, students, and watershed organizations. 

Data Quality Tiers

For the purposes of evaluating data submitted for Maryland’s Integrated Report, Maryland originally maintained a two-tiered approach to data quality.  For the 2020 IR, Maryland reevaluated the system to promote greater consistency with Virginia Department of Environmental Quality (DEQ) and The Chesapeake Monitoring Cooperative and has refined the data evaluation process to incorporate three tiers of data quality.
MDE’s data tiers may vary from the Chesapeake Monitoring Cooperative’s data tiers due to the regulatory basis of the IR.  The MDE tiers are based on data quality and the authorized uses of the data provided to the agency.  The tiers increase from Tier I to Tier III in conjunction with greater data standardization and quality assurance/ quality control (QA/QC) protocols.  Definitions and uses of each tier are outlined below. ​

Tier III- Approved by MDE

Definition: Tier III data are legally defensible data that can be used for regulatory decision-making purposes.
Appropriate Data Uses:
  • List or delist waters (Category 2 or Category 5) on the Integrated Report (IR);
  • Assess waters for IR;
  • Attainment purposes;
  • Use with State data for TMDL development, and
  • All uses listed in Tiers I and II.
  • These data must be accompanied by a Quality Assurance Project Plan (QAPP) consistent with EPA data guidance specified in Guidance for Quality Assurance Project Plans (U.S. EPA 2002a). Click here for the EPA guidance on QAPPs.
  • Documentation of field sampling and/or lab testing protocols or SOPs required.
  • This information must be consistent with Maryland’s Assessment Methodologies.

Tier II - Partially Approved by MDE

Definition: Tier II data are data with a defined methodology but do not meet Tier III data requirements and are not used to make regulatory assessment decisions (Category 2 or Category 5 of the IR).  However, waters with this level of data may be placed in Category 3 of the IR, denoting that there are insufficient data to make an assessment but that follow up monitoring is necessary.
 Appropriate Data Uses:
  • Track performance of TMDL implementation;
  • Category 3 designations for the IR;
  • Help target stream segments for water quality standards attainment assessments;
  • Be used as initial screening for listing or delisting waters (Category 2 or Category 5) on the Integrated Report (IR);
  • Identify waters for MDE follow up monitoring, and
  • All uses listed in Tier I.
  • These data should be accompanied by a Quality Assurance Project Plan (QAPP) consistent with EPA data guidance specified in Guidance for Quality Assurance Project Plans (U.S. EPA 2002a) or other equivalent documentation.
  • Field sampling and/or lab testing protocols or SOPs.
  • This information may use a monitoring method similar to MDE protocols but not fully approved by MDE due to differences in sampling or testing methodology.  ​

Tier I- Not Approved by MDE for Assessment

Definition: Tier I data do not meet the requirements of Tier II and Tier III but are of known quality and as a result still contribute to understanding of the health of the Chesapeake Bay watershed.
Appropriate Data Uses:
  • Educational or outreach purposes;
  • Location information on where monitoring is taking place;
  • Baseline data;
  • Notification of Possible Pollution Events;
  • Assess the general condition of surface waters in Maryland;
  • Identify waters for MDE follow up monitoring, and
  • Highlight local, community projects that are implemented to improve the health of the Bay watershed.
  • No Quality Assurance Project Plan (QAPP) or SOP required by MDE.
  • Uniform methodology recommended.
  • QAPP, SOPs and/or lab methods do not meet MDE quality assurance/quality control requirements.
  • May include land use data, visual observations of water quality condition, or data not consistent with Maryland’s Assessment Methodologies.
** Much of this text for this section was borrowed from Virginia DEQ and Chesapeake Monitoring Cooperative webpages on their Data Levels or Tiers.,  and


The purpose of the Integrated Report is to identify and list waters not meeting water quality standards (see Code of Maryland Regulations 26.08.02).  The most frequently assessed parameters for the Integrated Report include pH, dissolved oxygen (DO), turbidity (in NTU), biology, and bacteria.  Maryland does not have water quality criteria for some commonly monitored parameters such as nutrients, suspended solids, or water clarity for nontidal waters (Secchi depth).  

Bacteria is a popular parameter to monitor, but its use for recreational criteria, especially in non-beach areas, needs to be carefully considered.  Before submitting bacteria data for the Integrated Report, please see our Fact Sheet: Considerations for Bacteria Sampling at Non-Beach Areas.  Please contact Heather Merritt at or Becky Monahan at with questions about using bacteria data for the Integrated Report.  

For additional information about water quality standards, please visit MDE's Water Quality Standards Page. For more information on assessment methodologies, please visit MDE's Assessment Methodologies Page.

Quality Control of Water Quality Datasets

Data quality in Maryland’s water monitoring programs is defined through implementation of the agency’s quality control program (e.g. DNR’s and MDE’s Quality Management Plan), QAPP for each monitoring program, and field and laboratory Standard Operating Procedures (SOP). Water monitoring programs conducted under contract to EPA must have QAPPs approved by the EPA Regional or Chesapeake Bay Program Quality Assurance (QA) Officer prior to initiating monitoring activities.

Details in each program’s QAPP define data quality indicators by establishing quality control and measurement performance criteria as part of the program’s planning and development. Such measures help ensure there is a well-defined system in place to assess and ensure the quality of the data.

Water monitoring programs conducted by a local agency, educational institution, consultant or citizen group that intend to have their data used for regulatory decisions (Tier III data) should have a QAPP consistent with EPA data guidance specified in Guidance for QAPPs (U.S. EPA 2002a).  For state analysts to review these contributed data with any confidence, the quantitative aspects of these data need to be defined.
Some of the data quality aspects that need to be considered include:
​​​​​Precision - precision is how close the measurements are to each other. How reproducible is the data? Are sample collection, handling and analytical work done consistently each time samples are collected and processed?
​​Accuracy/Bias -Accuracy is how close a given set of measurements (observations or readings) are to their true value? How well do the measurements reflect what is actually in the sample? How far away are results from the “true” value, and are the measures consistently above or below this value?
Representativeness - How well do the sample data characterize ambient environmental conditions?
Comparability – How similar are results from other studies or from similar locations of the same study, or from different times of the year, etc.? Are similar sampling and analytical methods followed to ensure comparability? Do observations of field conditions support or explain poor comparability?
Completeness – Is the quality and amount of data collected sufficient to assess water quality conditions or can this data be appended to other, existing data collected at the same site or nearby to provide enough information to make an assessment decision?
​Sensitivity - Are the field and/or laboratory methods sensitive enough to quantify parameters at or below the regulatory standards and at what threshold can an analytical measure maintain confidence in results?

QAPPs will likely not address all of these issues and there are often no quantitative tests or insufficient Quality Control (QC) data available to do so. In these instances, best professional judgment may be required as these aspects can be difficult to address, even if there is a monitoring QAPP. For some issues, there is no quantitative test and often little, if any, quality assurance data provided with contributed data. In most instances, an analyst’s review of available monitoring program documentation and data are subjective. Once data quality is considered acceptable (or at least not objectionable), the dataset review process moves to a more quantitative review stage.

Water Quality Data Review

The designated uses defined in the Code of Maryland Regulations are assessed by relatively few field and analytical measures. Water temperature, dissolved oxygen, pH, turbidity, water clarity (Secchi depth or light extinction), acres of estuarine grasses, ammonia, biological integrity, and certain bacteria levels define the principal data used to assess criteria attainment. Various measures of nitrogen and phosphorus (nutrients) have not been defined in terms of criteria, although exceedance of dissolved oxygen or chlorophyll a criteria or nuisance levels of algae are attributed to high levels of nutrients. Except for special studies or as a discharge permit requirement, metals, inorganic and organic parameters defined as criteria are not routinely measured due to the high cost of analysis and few of these substances are found in ambient waters at levels exceeding criteria.  Specific toxins known to be directly related to human health (i.e., mercury and PCBs) are assessed through MDE’s fish and shellfish monitoring programs.

Water quality datasets reviewed for assessing use support are first examined in terms of a QAPP or other reports that define monitoring objectives and quality control. For selected parameters, the data are reviewed for sufficient sample size, data distribution (type and outliers/errors) and spatial and temporal distribution in the field. Censored data and field comments are examined for unusual events that may affect data quality (e.g., storm event). Data are examined for seasonality and known correlations (e.g., conductivity and salinity) are reviewed. Censored data are noted and may be excluded from the analysis.

Not all water quality criteria are assessed using this approach. Some assessments are conducted by other state programs using peer-reviewed or defined methods (e.g., Maryland’s assessment methodologies) and are not re-evaluated using other approaches. Examples include; assessment of algal samples, the state’s probabilistic non-tidal living resource survey (MD Biological Stream Survey), fish kill and bacterial assessments, bathing and shellfish harvesting restrictions, and toxic contaminants in fish tissue, shellstock and sediments.

Some criteria assessments are conducted externally by other agencies and programs such as VA institute of Marine Science, MD DNR, Versar, Inc., Old Dominion University, and EPA’s Chesapeake Bay Program. In these circumstances, the assessment methods are peer reviewed and results are provided to the state. Criteria assessed in this manner are not re-evaluated. Examples include; for Maryland’s Chesapeake Bay and tidal tributaries, benthic community criteria, aquatic grass coverage, water clarity, and dissolved oxygen. 

MDE supports the use of computer models and other innovative approaches to water quality monitoring and assessment.  Maryland and the Bay partners have also relied heavily on the Chesapeake Bay model to develop loading allocations, assess the effectiveness of best management practices, and guide implementation efforts. Several different modeling approaches have also been used in TMDL development.  With the large number of biological impairments in Category 5 of the IR, Maryland has been relying more heavily on land use analyses, GIS modeling, data mining, and other innovative approaches to identify stressors, define ecological processes, and develop TMDLs.

Need Technical Assistance for your Monitoring Program?

MDE and its partners can help your organization with monitoring program design to ensure the desired purpose is met to let you know state data needs. Please contact Becky Monahan at for more information.​

How to Submit Data to MDE

2024 Integrated Report Data Solicitation

For the 2024 Integrated Report (IR) of Surface Water Quality, MDE is accepting data from January 1, 2017- December 31, 2021.  In order to be used for the 2024 IR, all data must be submitted by December 30, 2022. Data submitted after this date will be reviewed in preparation of the 2026 IR.

All organizations interested in submitting data for the 2024 Integrated Report should fill out this Information Form. ​​
Then, there are two pathways to submit data: 
  1. Organizations that currently work with the Chesapeake Monitoring Cooperative (CMC)
    • ​​Please submit the information form above.  Then MDE will pull the applicable data from the Chesapeake Data Explorer on or near January 1, 2023.  Please work with Liz Chudoba at the CMC to ensure that your data are up to date in the Data Explorer.  Email Liz at with any questions. 
  2. ​All other organizations
    • ​​Please submit the information form above.  Then email data directly to Becky Monahan at by December 30, 2022.  If the dataset is large, a google drive sharing option can be set up.  Please include a brief description of your data and all applicable metadata including Standard Operating Procedures (SOPs) or Quality Assurance Project Plans (QAPPs).  
Because the IR is a regulatory document, some data received may not be suitable for water quality assessments. In addition, data pulled from the Chesapeake Data Explorer may be in a different data tier for MDE assessment purposes.  Please see more information in our MDE Data Quality Tiers section below. The Department will track all data received and data submitters can contact MDE to inquire how their data were used and why.  
Please contact Becky Monahan at 410-537-3947 or with any questions related to data submission.​

For additional IR information, please visit MDE’s Integrated Report Web page.​​​​


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