1 Module 2: Enhanced Systems When it’s more than a straight pipe from the catch basin to the waterbody Stormwater System Maintenance: A 4-Part Workshop Series

2 Today we will review How we identify & describe structural BMPs How we inspect, clean & repair structural BMPs

3 We will Review the goals as written in the General Permit Clarify or expand as needed Review what we are doing now Review how we report our activities Look for ways to improve our effectiveness and/or efficiency

4 O&M Program Required Goal – Identify, locate & describe all structural BMPs owned or operated by the MS4 operator

5 What are Structural BMPs?

6 Why do we have them? In response to the changes in stormwater runoff as land use changed from undeveloped to developed

7 What are they supposed to do? First generation: flood control –Late 1970’s, early to mid-80’s –Requirement incorporated into subdivision regulations Second generation: water quality benefits (treat pollutants) –Mid to late 1980’s –Modified basin designs –Proprietary structures –Focus on total suspended solids (TSS) Current emphasis: improved treatment and volume control –Low Impact Development (LID) –Small scale controls

8 The Smart Development for a Cleaner Bay Act of 2007 Amend Stormwater Design & Installation Standards Manual Regulatory programs require use of low- impact design techniques

9 Runoff from our watersheds Flows to city/town system Flows to other MS4s Flows to State system Flows to private system Flows directly to stream, pond, etc. (Chart for illustrative purposes only, based on Best Professional Judgment of Southern RI Conservation District)

10 Our stormwater system Pipe directly to surface water Flow to private BMP or other MS4 Flow to MS4 BMP (Chart for illustrative purposes only, based on Best Professional Judgment of Southern RI Conservation District)

11 Private Structures Municipality permitted development based on some level of water management Municipal system now dependent to some degree on BMPs functioning properly Therefore, need to know where they are & what condition they are in

12 Private Structures Post-Construction Minimum Measure requires us to identify private BMPs, inspect and enforce O&M

13 Ideal You know where & how stormwater runoff flows in the watersheds of your MS4 You know who’s responsible for the performance of each system

14 You know: Where structures are What condition they’re in Who is responsible

15 Problems? Records of what’s gone on the ground in the past thirty years may have slipped through the cracks –May not know where all structures are –May not have designs/as-builts –May not know who’s responsible for maintenance –May not have O&M plans

16 Our Structural BMP Inventory Maps Database Update

17 Why a Database? Track maintenance and inspection Streamline processes –Scheduling inspections/maintenance –Sending notices to private owners –Reporting Provide documentation Develop program cost estimates Identify retrofit opportunities Evaluate program effectiveness

18 RIGL (b) “A regulated small MS4 shall designate…those storm drainage systems that are prone to street flooding and/or contribute significantly to storm water management problems.” Structural BMPs included in definition of “storm drainage system”

19 Updating Required Update –As new structures are installed –As forgotten structures are found –As maintenance is performed Report –Include in MS4 Annual Report

20 What if I find “something” that’s not on the map, or an error in the map? Note the location on a copy of the map Describe the structure and its condition, or note what the error is Submit the map and note to the Engineering office

21 O&M Program Required Goal – Procedures for inspections, cleaning & repair of detention/retention basins and related storm sewers, catch basins Inspection & maintenance schedule BMP-specific as approved, modify based on reports Maintain records

22 How is a BMP supposed to work? Runoff from a given area (catchment) is directed to a structure

23 Design peak flow is over Water infiltrates Solids settle out Pollutants are filtered or taken up by vegetation A structural BMP holds the water back until at least one of the following occurs

24 Performance depends on ENVIRONMENTAL CONDITIONS –Actual climate & catchment conditions are similar to design conditions BMP CONDITIONS –Well-designed –Built as designed –Maintained MAINTENANCE IS REQUIRED

25 Common Performance Problems Structure volumes are insufficient for the amount of water they receive –May have been sized/built wrong –Catchment may have changed (size and/or land use) –Volume may be reduced by sediment, vegetation and/or litter

26 Swale completely filled with sediment, vegetation and debris (Inlet buried)

27 Common Performance Problems Outlet controls don’t function as intended –Design errors –Installation errors Especially compaction of infiltration systems –Controls are clogged by sediment, vegetation and/or litter –Mechanical controls are broken –Cumulative impact

28 What is cumulative impact? Multiple structures, each slowly releasing increased runoff Results in increased volume of water moving downstream Timing of releases can increase flooding

29 How do we know if a structure is performing well? INSPECT

30 Our Inspection Procedures Schedule –Routine inspections –Non-routine inspections Inspection forms Post-storm checks Reports

31 RIGL “…systems prone to flooding or contributing significantly to storm water management problems shall be inspected at least once per year…”

32 Ideal Inspection Schedule Routine –Two times per year –After every big storm (blockage of inlets or outlets) Non-routine to be scheduled based on –Physical condition noted in routine inspection –Tendency to flood –Watershed address

33 Routine Inspections Unexpected ponding Obstructions of inlet or outlet Cracking or settling Excessive erosion or sedimentation Signs of dumping or vandalism Encroachment Healthy vegetation under control Pipes, fences, etc. in good condition Stability of sideslopes & downstream channel Emergency spillway in good condition

34 Non-routine inspection Need original design/as-built for comparison –Check structure volume –Check size, types of inlets, outlets –Check elevations Dam/top of structure Inlets Outlets –Verify catchment assumptions

35 BMP Maintenance Customized O&M Plan Permit requirements Inspection results

36 Routine maintenance Vegetation control by mowing or removal of undesired plants Debris & litter control Minor bank stabilization & erosion control Access to inlets & outlets maintained

37 Non-routine maintenance Mechanical components Sediment removal Recondition soils for infiltration Replacement/retrofit

38 Remember Safety!!

39 Waste Disposal Trash & litter to landfill Vegetation to compost or chipper Dewater sediments –Use as daily cover or –Test for use as fill

40 Using results of maintenance records Revise inspection & maintenance schedules Improve design, site plan review for ease of maintenance Evaluate opportunities for retrofit Improve program cost estimates

41 Enhanced Systems Structure purpose: –Reduce flooding –Improve water quality Good Housekeeping purpose: –Enable structures to perform adequately

42 Stormwater System Maintenance: Employee Training Brought to you by: This program was developed by the Southern Rhode Island Conservation District in partnership with the URI Cooperative Extension RI NEMO Program and the Rhode Island T2 Center. Funding was provided by the RI Department of Environmental Management and the RI Department of Transportation under the Phase II Stormwater Education and Outreach Project.