The primary reasons for a permittee to perform monitoring of receiving waters are to (a) evaluate the impact of TMDL implementation strategies enacted throughout the watershed, and (b) evaluate impairment status to determine if the impaired waterbody can be removed (i.e., delisted) from the 303(d) Impaired Waters List. The following subsections outline the basics of developing a monitoring program to meet goals established within the Guidance Manual for Assessing Quality of Minnesota Surface Waters for Determination of Impairment: 305(b) Report and 303(d) List (MPCA, 2018a), and developing a monitoring protocol standard operating procedure (SOP). Specifically, the Establishing a Monitoring Program section provides guidance on when, where, and what to sample, while the Establishing a Monitoring Protocol section provides guidance on how to sample (i.e., sampling SOP).
Before developing or implementing a lake monitoring program, the applicable TMDL(s) should be reviewed to determine (a) if an ongoing water quality monitoring program exists or will be implemented and (b) what organization(s) are responsible for water quality monitoring (e.g., individual permitteess, the applicable Watershed District or Watershed Management Organization (WMO), etc.). Review of ongoing and planned water quality monitoring programs can help a permittee optimize sampling procedures to supplement ongoing monitoring efforts and help identify potential partnering opportunities with other organizations (e.g., WDs, WMOs, Citizen-Assisted Monitoring Program (CAMP), Soil and Water Conservation Districts (SWCDs), Metropolitan Council, etc.). To encourage statewide water quality monitoring efforts, the MPCA offers Surface Water Assessment Grants (SWAG) to eligible partners, including MS4s. More information on SWAG requirements and grant application can be found on the MPCA’s Surface Water Assessment Grants webpage.
In addition to review of planned or ongoing monitoring programs, the applicable TMDL(s) should be reviewed to determine the specific water quality standard(s) that apply to the impaired waterbody. Water quality standards applicable to the impaired waterbody are specific to the pollutant (e.g., chloride), the water body type (e.g., lake), and the water use classification (e.g., Class 2A).
The following subsections outline specific lake monitoring program requirements related to each of the four (4) pollutants discussed on this page: total suspended solids (TSS), total phosphorus (TP), bacteria, and chloride.
As of 2018 Minnesota Impaired Waters List (MPCA, 2018b) there are no lakes listed as impaired for TSS. For more information regarding establishing a TSS monitoring program for streams, link here.
Lake eutrophication water quality standards established in the Minnesota Rule, Chapter 7050 (MINN. R. 7050, 2018) require paired observations of TP, chlorophyll-a, and Secchi disk transparency during the summer period (June 1 through September 30) of the monitoring year. From Part 7050.0222, Subp. 2a:
Eutrophication standards for lakes and reservoirs are compared to summer-average data. Exceedance of the total phosphorus and either the chlorophyll-a or Secchi disk transparency standard is required to indicate a polluted condition.
The numeric standards for TP, chlorophyll-a, and Secchi disk transparency vary by use classification (e.g., Class 2B), ecoregion (e.g., North Central Hardwood Forests), and by lake classification (e.g., trout lake, shallow lake, etc.). The applicable water quality standards for the impaired waterbody are outlined in the applicable TMDL report. Based on Minnesota lake eutrophication standards and specific impairment assessment and delisting requirements for lake eutrophication, the following list outlines specific recommendations to develop a lake eutrophication monitoring program. Specific monitoring protocol recommendations are discussed here.
Lake Eutrophication Monitoring Program Recommendations
As of the 2018 Minnesota Impaired Waters List (MPCA, 2018b) there are no lakes listed as impaired for Escherichia coli (E. coli). For more information regarding establishing an E. coli monitoring program for streams, link here.
Chloride water quality standards within Minnesota Rule, Chapter 7050 (MINN. R. 7050, 2018) are consistent for all Minnesota waters (i.e., all use classifications). Specifically, Minnesota Rules define a chronic toxicity-based chloride water quality standard of 230 mg/L (i.e., chronic standard), and an acute toxicity standard of 860 mg/L (i.e., maximum standard). Specific data requirements for evaluation of impairment condition for both the chronic and maximum chloride water quality standard established in the Guidance Manual for Assessing the Quality of Minnesota Surface Waters for Determination of Impairment: 305(b) Report and 303(d) List (MPAC, 2014) are outlined below.
The MPCA has published several Statewide Chloride Resources, including the Draft Statewide Chloride Management Plan (MPCA, 2019) and specific protocols related to stream and lake chloride monitoring.
Based on review of chloride standards, statewide guidance documents, and specific impairment assessment and delisting requirements for chloride impairment, the following list outlines specific recommendations for developing a lake chloride monitoring program. Specific monitoring protocol recommendations are discussed here.
Chloride Monitoring Program Recommendations
The MPCA has specific requirements and protocols related to water quality data collection, laboratory processing of water quality samples, data processing of laboratory results, and final submittal of water quality data to the MPCA for review. Specifically, the MPCA uses a data processing system called EQuIS (Environmental Quality Information System) to store and process water quality data collected from over 17,000 sampling locations across the state, and requires that data be collected and processed in a manner which is compatible with EQuIS.
There are many publicly available Quality Assurance Project Plan (QAPP) and monitoring Standard Operating Procedure (SOP) documents which can be used as a framework for developing a monitoring protocol. The following subsections provide an overview of EQuIS requirements and a summary of lake and stream monitoring QAPP and SOP documents.
The MPCA has developed extensive guidance related to establishing EQuIS projects, and developed tools and guidance to assist monitoring and laboratory staff to process data in an EQuIS-compatible format. The following steps provide a basic overview of the EQuIS data collection and submittal process: establishing an EQuIS project, processing collected water quality data, and submitting collected data to the MPCA for review. Collecting, processing, and submitting EQuIS data requires contact and coordination with an MPCA EQuIS team member.
The primary objective of a QAPP is to define the data quality assurance (QA) goals and procedures applicable to a monitoring program (MCES, 2003). A lake or stream monitoring QAPP must also provide an overview of program design (e.g., program organization, responsibilities, monitoring parameters, sampling locations, etc.), and must define sampling methods (e.g., sampling locations and monitored variables), analytical procedures, QA procedures, and data review protocols.
For this reason, a QAPP document may also contains monitoring SOP(s), defining sampling procedures, field analysis, laboratory analysis, and data review and QAQC measures.
The following subsections provide a summary of monitoring QAPP documents which can be used as templates for developing a lake or stream monitoring QAPP.
The MCES Quality Assurance Program Plan: Stream Monitoring (MCES, 2003; updated 2011) is a QAPP for the MCES’s Nonpoint Source Pollution Monitoring Program and Watershed Outlet Monitoring Program (WOMP). The QAPP defines goals, objectives, program organization, responsible parties, specific sampling procedures and protocols (e.g. monitoring SOPs, QA procedures, laboratory analytical procedures, etc.), and the monitoring locations, monitored variables, and monitoring frequency for both stream monitoring programs. Specifically, the QAPP is organized into the following sections:
The organization of the MCES Stream Monitoring QAPP can be used as template for the development of a stream or lake monitoring QAPP. In addition to defining the organization, goals, and QA procedures for the monitoring programs, the QAPP also includes sampling, field analysis, laboratory analysis, and data review SOPs as appendices to the document. The SOPs outline specific monitoring procedures to be followed in the field (e.g., equipment checklist, grab sample bottle and equipment cleaning, field duplicate collection and labeling, health and safety procedures, etc.). Monitoring SOPs are discussed in more detail below.
The MPCA and United States Environmental Protection Agency (USEPA) have developed many guidance documents related to QA and the development of QAPPs. Specific QAPP guidance documents and QA tools are summarized below:
Questions related to QAPP development, QA procedures, or the references listed above can be directed to any of the MPCA QA coordinators listed in the “Contacts” section of the MPCA Quality System webpage.
As discussed above, a monitoring standard operating procedure (SOP) is a critical component of a complete monitoring QAPP. A monitoring SOP defines specific protocols related to field sample collection and laboratory analysis, and often also includes pre-field protocols (e.g., equipment and supply checklist, pre-field bottle preparation and labeling, etc.), post-sampling protocols (e.g., sample preparation and preservation, sample chain of custody, etc.) and other protocols not specifically related to monitoring and sample collection (e.g., boat and canoe preparation, health and safety, inclement weather protocols, etc.).
The following subsections provide a summary of monitoring SOP documents which can be used as templates for developing a lake or stream monitoring SOP. It is recommended that the documents discussed in this section be used in conjunction with specific monitoring guidance outlined in the applicable TMDL when developing a lake or stream monitoring SOP.
NOTE: See example case studies in which monitoring was used to help identify pollutant sources, evaluate the impact of implementation strategies, and ultimately delist a formerly-impaired water body.
The Standard Operating Procedures: Intensive Watershed Monitoring – Lake Water Quality Sampling (MPCA, 2018c) and Standard Operation Procedures: Intensive Watershed Monitoring – Stream Water Quality Component (MPCA, 2018d) are SOPs created by the MPCA for local partners contracted through the MPCA’s Surface Water Assessment Grants Program. The SOP outlines sampling procedures applicable to all Minnesota lakes and streams, including pre-sampling requirements, equipment and supply checklists, on-site sampling procedures, QAQC procedures (e.g., field sample duplicates), post-sampling procedures, and a detailed discussion of health and safety protocols. In addition to pre- and post-sampling procedures, the SOP discusses bottle labeling and the chain of custody (COC) procedures for delivering samples to State-certified laboratories, and final data preparation and submittal to EQuIS.
The MPCA, USEPA, and MCES have developed many publically available guidance documents related to the development of surface water monitoring SOPs. Specific SOP documents which be used as templates to develop a surface water monitoring SOP are summarized below. It is recommended that the documents discussed in this section be used in conjunction with specific monitoring guidance outlined in the applicable TMDL when developing a lake or stream monitoring SOP:
Questions related to SOP development can be directed to any of the MPCA QA coordinators listed in the “Contacts” section of the MPCA Quality System webpage.
TMDL MS4 permit guidance
TMDL toolkit for MS4 permit compliance
TMDL guidance and general information