Summary of I. Introduction to Section 5 Summary of I. Introduction to Section 5

Summary

Chapter 5 presents a compilation of Best Management Practices (BMPs) that are specifically applicable to public drainage systems in Minnesota. The chapter and its contents support the work of ditch authorities, their staff and engineers by providing guidance and tools to address design, maintenance, repair, and water quality and quantity issues on and in the watershed of Minn. Stat. 103E drainage systems.

Chapter 5 provides a resource for users with varied levels of experience using BMPs on Minn. Stat. Chapter 103E systems. Reference to relevant statutes, a BMP Table, and BMP definitions are provided.

The BMPs provided support Minn. Stat. Chapter 103E Drainage Law in two (2) primary ways:

1. BMPs that provide information and support for drainage authorities work through the drainage system design and construction considerations required by:

• i. Minn. Stat. 103E.015, Considerations Before Drainage Work is Done, subd. 1, 1(a), and 2

2. BMPs that supplement and enhance drainage system repair, maintenance, and management activities addressed by:

• i. Minn. Stat. 103E.021, Ditches Must Be Planted With Perennial Vegetation, subds. 1, 2, and 6;

• ii. Minn. Stat. 103E.227, Impounding, Rerouting, and Diverting Drainage System Waters, subd. 1(a);

• iii. Minn. Stat. 103E.701, Repairs, subd. 1 and 6;

• iv. Minn. Stat. 103E.705, Repair Procedure, subds. 1 and 3; and

• v. Minn. Stat. 103E.715, Procedure for Repair by Petition, subd. 6.

For the purposes of this manual, a BMP is a structural or non-structural practice that minimizes water quality and/or quantity (peak flow or volume reduction) impacts within a public drainage system or its watershed.

There are two (2) types of BMPs:
1. On-System
On-system BMPs are used within a Chapter 103E drainage system and include any statute-allowed, or required practice (i.e., vegetated buffer strips, grade control structures, side inlets, erosion control, multi-stage ditch, water storage, restored wetland, culvert sizing, resloping, tile repair, etc.). Many of such practices do not have a design standard.

2. Off-System
BMPs implemented off the Chapter 103E drainage system are not within the traditional purview of the drainage authority. Practices applied on fields and farms in the watershed of system can provide significant benefits downslope to the drainage system. Drainage inspectors and drainage system engineers should be aware of the potential for off-system BMPs to solve on-system problems.

• Typical structural off-system BMPs: Water and sediment control basins, grass waterways, Drainage Water Management (DWM); and

• Typical non-structural off-system BMPs: nutrient management, cover crops, conservation tillage, etc.

Other resources from which the BMPs provided within this chapter are also cited include (Chapter 5, Section I, E):

• Minnesota Stormwater Manual;

• USDA’s Field Office Technical Guide (FOTG)/The Ag BMP Handbook for Minnesota;

• NRCS Engineering Field Handbook; and

• Red River Basin TSAC, Technical Paper No. 15.

The suggested method for navigating through the BMP identification process and how to use Chapter 5 includes three (3) steps (Chapter 5, Section I, F):

• Step 1: Observe and identify potential problems and opportunities;

• Step 2: Determine the cause of the problem; and

• Step 3: Select an appropriate BMP solution to address the problem/symptom or cause (Use of the BMP Table).

The Best Management Practices (BMPs) Table sorted by issue/cause and on-system and off-system BMP solutions, along with BMP definitions are provided within Chapter 5, Section II.