Operation & Maintenance of Permanent Stormwater Controls Overview of Inspection Requirements Laura Prickett, AICP, CPESC EOA, Inc. Construction Inspection.

Operation & Maintenanceof Permanent Stormwater

ControlsOverview of Inspection Requirements

Laura Prickett, AICP, CPESC EOA, Inc.

Construction Inspection WorkshopApril 11, 2013

Outline of Presentation

Permanent Stormwater Controls that Require O&M Verification Inspections

O&M Requirements in the Municipal Regional Stormwater Permit

The O&M Verification Inspection Plan

Tools for Conducting, Tracking and Reporting O&M Inspections

For more information…

Permanent Facilities that Require O&M Inspections

Provision C.3.h of the MRP requires agencies to conduct inspections to verify operation & maintenance (O&M) of: • Stormwater treatment measures, and • Hydromodification management measures

Stormwater Treatment Measures

Engineered systems that remove pollutants from stormwater runoff

Bioretention Area (biotreatment)Bioretention Area (biotreatment)

Stormwater Treatment Measures

Engineered systems that remove pollutants from stormwater runoff

Media Filter (limited use for Special Projects)

Media Filter (limited use for Special Projects)

Hydromodification Management (HM) Facilities

Reduce development-induced erosion Detain stormwater so that post-project

peak flows and durations match pre-project conditions for a range of flows.

Hydromodification Management (HM) Facilities

Basins, tanks or vaults with specialized outlet that slowly releases water.

Detention basin with specialized outletDetention basin with specialized outlet

O&M Requirements (Provision C.3.h)

Agencies subject to the MRP must: • Require facility owners to conduct ongoing

maintenance (e.g. , maintenance agreement).• Prepare and implement plan for annual O&M

verification inspections, including new installations.

• Conduct O&M verification inspections; provide enforcement as needed.

• Track and report on inspections.

What about Municipality-owned Facilities?

O&M inspection requirements do not distiguish between municipal and non-municipal facilities.

Inspect, track and report on facilities that your municipality is responsible for maintaining.

O&M Verification Inspection Plan

Begin implementing by 12/1/10. Each fiscal year, inspect:• All newly installed stormwater treatment and

HM controls within 45 days of installation• 20% of the total number of installed stormwater

treatment and HM controls (when rounding, round up!)

• 20% of all installed vault-based systems (round up)

All installed treatment and HM facilities must be inspected at least once every 5 years.

Lessons Learned from NOVs

Round up when calculating 20 percent of facilities per year. • If your agency has fewer than 5 facilities, be

sure to inspect one per year.

Tools for Inspecting, Tracking & Reporting

O&M Verification Inspection Checklist Annual Report Table Each agency should have an internal

tracking table, which is NOT submitted with Annual Report.

O&M Verification Checklist

Example Tracking TableMRP Attachment G-1

DRAFT Annual Report FormC.3.h Reporting Table

For More Information…

Countywide Program Password Protected ND page www.flowstobay.org (click on “Municipalities,” then “ND”)• O&M Verification Inspection Plan Template• O&M Verification Inspection Checklist• Model maintenance agreement

Municipal Regional Stormwater Permit www.flowstobay.org (click on “Municipalities,” then scroll to “Municipal Stormwater Permit”)

May conduct as part of overall final inspection of constructed project UNLESS:• Stormwater treatment and/or HM facilities become operational

earlier, IN WHICH CASE—Inspect and approve stormwater facilities before they become operational

Common Issues in Inspections of Newly-Installed Treatment

Measures

Laura Prickett, AICP, CPESCEOA, Inc.

Construction Inspection WorkshopApril 11, 2013

Outline

Purpose of inspection What to look for during inspection Common issues Checklist for 45-day inspection

Purpose of Inspection

Verify treatment measures and/or hydromodification management controls are installed per approved plans.

At a minimum, inspect those components that are visible in the finished condition.

If possible, also inspect below grade components during construction.

Prepare for the Inspection Review project plans to identify:• The number of treatment measures and/or

HM systems to be installed on the site.• The locations of treatment measures

and/or HM systems.• The dimensions of treatment measures

and/or HM systems.

Prepare for the Inspection

Review project plans to identify:• How high flows will be managed/diverted.• Type and extent of plant cover.• Type of approved irrigation system.

In this system, high flows will enter raised inlet.

During the Inspection

Confirm that installation matches approved plans regarding:• Total number and type(s) of facilities.• Location of facilities on the site.• Dimensions of facilities.• Request confirmation from site

superintendent that biotreatment soil is per MRP specifications.

During the Inspection

Confirm that installation matches approved plans regarding:• Type and extent of plant cover.• Functional irrigation system.• High-flow bypass or overflow path.

Overflow drain designed to keep out trash and debris.

Common Issues Is there exposed soil?• Exposed soil should be covered with 2” of

mulch, except for area immediately surrounding tree trunks (roots need air).

Will vegetation block inlets to the treatment measure when mature?

Turf is blocking inlet; insufficient drop between pavement and top of grade in planting area.

Common Issues Is there positive drainage to the

treatment measures? Is there permanent erosion control at

points of concentrated flow?

Cobbles reduce erosion at entrance to bioretention area.

Common Issues Are plants healthy? Accumulation of sediment from

construction activity? • Accumulated sediment must be removed.

O&M Verification ChecklistMay be used for 45-Day inspections; will have to

use “Comments” section

Thank you!

Laura Prickett, AICP, CPESCEOA, Inc.

510.832.2852 x [email protected]