MPCA Infiltration Device - Pond Requirements

The use of stormwater infiltration has been a popular choice for stormwater management for many years. The benefits of infiltration include reducing overall run-off volume, reducing stormwater and channel run-off rates, and reducing pollutant loading.

However, infiltration can also create other issues, including groundwater contamination. Infiltration of stormwater (and the wastes it carries) may also invoke other environmental regulations.

The Minnesota Pollution Control Agency has incorporated requirements for the use of both infiltration devices and stormwater ponds used to manage industrial site runoff. These requirements include:

1. Industrial stormwater ponds and infiltration devices located in areas where high levels of contaminants exist in the soil or in the shallow aquifer, must not contribute to contaminant(s) spreading to a greater extent or rate. At any contamination site, a site analysis shall be conducted and a report filed with the SWPPP.

a. If industrial stormwater ponds and infiltration devices are found to be a contributor to contaminant increase or movement, the site must submit a plan to MPCA that describes how they will be reducing contaminants, redesigning, relocating, or eliminating the industrial stormwater ponds and infiltration devices, as needed, to eliminate the contribution to contaminant problems.

2. Industrial stormwater ponds and infiltration devices can not be used in any high risk karst area unless a professional geotechnical evaluation is conducted to ensure that they do not present a significant risk to groundwater.

a. If the industrial stormwater ponds and infiltration devices present a risk, appropriate measures, such as sealing or removal of the industrial stormwater ponds or infiltration devices, must be taken to eliminate or minimize the risk. Evaluations shall be documented with the SWPPP.

3. Use of industrial stormwater ponds and infiltration devices in vulnerable wellhead protection areas must be coordinated with local drinking water authorities and shall be designed to not adversely affect drinking water supplies. The facility must contact the appropriate local drinking water authorities and document coordination efforts with the SWPPP.

4. Facilities using any infiltration device defined as a “Class V injection well” shall contact the US EPA Region HQ to determine the need to register as a “Class V injection well”. Contacts and USEPA response need be documented with the SWPPP.

Caltha LLP provides expert consulting services to public and private sector clients nationwide to address Stormwater Permitting & Regulatory Support, Stormwater Pollution Prevention Plans (SWPPP), Stormwater Monitoring and Stormwater Training.

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Massachusetts DEP Proposed Stormwater Regulations

The Massachusetts Department of Environmental Protection (DEP) is proposing a new approach to stormwater management which will require private owners of large impervious surfaces (including institutions, commercial, industrial and residential properties) to manage stormwater. The draft requirements include:

• Statewide private property owners of impervious surfaces ≥5 acres will be required to implement good housekeeping practices,
• Statewide private new developments with impervious surfaces ≥5 acres will be required to meet the state’s Stormwater Standards 3-6, including recharge and water quality treatment,
• Redevelopments with impervious surfaces ≥5 acres must maintain the same level of stormwater control and recharge, to the extent site constraints allow.

In areas that drain to an impaired waters with an existing or pending TMDL, a 65 % reduction in phosphorus load is required to achieve compliance with the State’s water quality standards.

Private property owners of impervious surfaces ≥2 acres will also be have requirements under the new program. New projects and redevelopments will have to meet statewide requirements and implement stormwater Best Management Practices (BMPs) capable of reducing phosphorus. Existing properties will be given 10 years to retrofit their properties to meet the phosphorus reduction requirement. TMDL areas include the Charles River watershed (with a 65% phosphorus reduction requirement) and a number of lake watersheds across the state.

Caltha LLP provides expert consulting services to public and private sector clients nationwide to address Stormwater Permitting & Regulatory Support, Stormwater Pollution Prevention Plans (SWPPP), Stormwater Monitoring and Stormwater Training.

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WDNR Runoff Standards - Proposed Amendment to NR 151

The Wisconsin Department of Natural Resources (WDNR) is currently in the process of making revisions to Wisconsin Rule NR 151. NR 151establishes runoff pollution performance standards for non−agricultural facilities and transportation facilities and performance standards and prohibitions for agricultural facilities and practices designed to achieve water quality standards.

The WDNR has proposed amendments that include:

• develop an agricultural buffer or equivalent performance standard and a performance standard to address sediment, manure and other runoff from smaller, non-permitted farms;
• modify post-construction non-agricultural performance standards, regarding infiltration and protective areas;
• revise existing agricultural performance standards and prohibitions to clarify provisions related to manure storage facility closures and direct runoff of manure; and
• modify grant rules pertaining to eligibility, awards, allocation for TMDLs and project size.

A formal proposal for amendments is expected to be released for public comment in 2009.

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Stormwater Infiltration - Regulatory and Permitting Aspects

Infiltration is used as a stormwater control or Best Management Practice (BMP) in many areas. However, infiltrating run-off has some unique regulatory issues. First, in some States, infiltrating stormwater is a viable means to eliminate a discharge that would otherwise require an NPDES discharge permit. However, in most cases, the system would need to infiltrate all run-off from even the largest rain events. In addition, seasonal changes must also be considered; all run-off would need be collected and infiltrated even during frozen conditions. Some States regulate groundwater as a "water of the State", and therefore can regulate discharges to the groundwater using infiltration.

Here are two recent examples:

New Hampshire. New Hampshire has recently proposed requiring a "Alteration of Terrain" permit for many types of new projects. Infiltration of stormwater is prohibited if the run-off comes from "high load areas", which include many typical industrial activities.

[Read more about New Hampshire Alteration of Terrain permits]

Minnesota. The Minnesota Pollution Control Agency (MPCA) has been drafting regulations relating to infiltration of stormwater at sites regulated under the industrial stormwater discharge general permit. These requirements are still in revision, however as of November 2008 the format for regulation of infiltration as a stormwater control has included:

• Design criteria for amount of run-off to be infiltrated


• Rate at which infiltration must occur after a storm event


• Pretreatment requirements for run-off prior to discharge to designed infiltration basin


• Stormwater monitoring requirements and standards ("benchmarks") for run-off prior to discharge to designed infiltration basin


• Operation and maintenance requirements.

The draft MPCA infiltration requirements also include several prohibitions, where infiltration can not be used to manage stormwater. These include:

• Certain industrial sectors are prohibited from using infiltration BMPs;


• Certain sensitive areas where groundwater is vulnerable to contamination, including karst areas, and well head protection areas.
  

Finally, under some circumstances the disposal of stormwater run-off using a designed infiltration system can be further regulated as a Class V Injection Well. This will require further permitting and associated regulation.

Caltha LLP provides expert technical support to clients nationwide in addressing stormwater permitting and SWPPP requirements.

[Read further information on Stormwater Plan - SWPPP Services]

[Read further information on Stormwater Training - SWPPP Training]

For further information contact Caltha LLP at
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NH Alteration of Terrain Permit – High Load Areas

The New Hampshire Department of Environmental Services (DES) has recently finalized new rules requiring an Alteration of Terrain Permit (AOT) for many types of construction projects. The purpose of these rules to protect drinking water supplies, surface waters, and groundwater by specifying the procedures and criteria for obtaining permits required by the rule. These rules shall apply to any person proposing to:
(a) Dredge, excavate, place fill, mine, transport forest products, or undertake construction in or on the borders of surface waters; or
(b) Significantly alter the characteristics of the terrain in such a manner as to impede the natural runoff or create an unnatural runoff.

One key aspect of the rule is the definition and requirements for “High-Load Areas”. High-load areas include:
(1) Industrial facilities subject to the NPDES Multi-Sector General Permit;
(2) Petroleum storage facilities;
(3) Petroleum dispensing facilities;
(4) Vehicle fueling facilities;
(5) Vehicle service, maintenance and equipment cleaning facilities;
(6) Fleet storage areas;
(7) Public works storage areas;
(8) Road salt facilities;
(9) Commercial nurseries;
(10) Non-residential facilities having uncoated metal roofs with a slope flatter than 20%;
(11) Facilities with outdoor storage, loading, or unloading of hazardous substances, regardless of the primary use of the facility; and
(12) Facilities subject to chemical inventory under EPCRA Section 312.

A Source Control Plan may need to be prepared and submitted to NHDES for any proposed projects that include high-load areas and larger commercial parking areas.

The new rule also details requirements that apply to stormwater management practices from high-load areas, which include:

• Prohibition on groundwater recharge;
• Prohibition on infiltration practices;
• Prohibition on stormwater filtering practices, without an impermeable liner; and
• Prohibition on stormwater swale practices, without an impermeable liner.
  

Caltha LLP provides expert technical support to clients nationwide to develop cost effective pollution prevention programs to meet State and Federal requirements.

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Infiltration Basins - Draft Requirement for Retrofit of Existing Basins

UPDATE: On July 6, 2009, MPCA is scheduled to release its proposed Multisector Industrial General Stormwater Permit. In July, Caltha LLP will be hosting seminars in several cities across Minnesota to provide information on the proposed permit and rule changes, and steps facilities can take to reduce their impact.

For more information, go to:

MPCA SWPPP Permit - Industrial Stormwater Permit Reissue Seminars

++++++++++++++++++++++++++

On December 18, 2008, the Minnesota Pollution Control Agency released a redraft of the Multisector Industrial General Permit (MSGP) currently being written. This version of the permit provides some additional requirements on the design of infiltration basins. [Read more about the regulatory aspects of infiltration basins]


As discussed previously, MPCA has included specific design and monitoring requirements for infiltrations basins. These include several situations and industrial sectors for which infiltration basins are forbidden.

One on the key elements of the MPCA requirements for infiltration basins is the RETROFIT of existing infiltration basins which do not currently meet the new design criteria. Existing infiltrations basins must be upgraded to meet the new requirements within one year of promulgation of the MSGP.

The MPCA MSGP is a work in progress; revisions and additions to the permit continue to be made. Once a draft is completed, the permit will be issued for public comment. Because of the size and complexity of the draft permit (especially compared to the current permit, written in 1997), it is expected that there will be significant public comments.

Caltha LLP provides expert technical support to industrial facilities nationwide subject to stormwater permitting requirements.

For further information contact Caltha LLP at
info@calthacompany.com
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New North Carolina (NCDENR) Stormwater Rules for Discharges to Sensitive Water

New Division of Water Quality stormwater rules became effective October 1, 2008 in North Carolina for coastal areas which drain to shellfishing areas or other high value water resources. The new rules regulate new development and redevelopment projects. The major areas for change are 1) coverage (non-residential), 2) low density thresholds, 3) design storm requirements, 4) wetlands and impervious surface calculations, and 5) vegetative buffer size.

In areas within one-half mile of shelling fishing areas, percent impervious cover must be <12%>MS4 stormwater discharge permits as they are reissued.

For further information contact Caltha LLP at
info@calthacompany.com
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Using Infiltration as Stormwater BMP - Regulatory Issues

Infiltration is used as a stormwater control or Best Management Practice (BMP) in many areas. However, infiltrating run-off has some unique regulatory issues. First, in some States, infiltrating stormwater is a viable means to eliminate a discharge that would otherwise require an NPDES discharge permit. However, in most cases, the system would need to infiltrate all run-off from even the largest rain events. In addition, seasonal changes must also be considered; all run-off would need be collected and infiltrated even during frozen conditions. Some States, such as Minnesota, regulate groundwater as a "water of the State", and therefore can regulate discharges to the groundwater using infiltration.

The Minnesota Pollution Control Agency (MPCA) has been drafting regulations relating to infiltration of stormwater at sites regulated under the industrial stormwater discharge general permit. These requirements are still in revision, however as of November 2008 the format for regulation of infiltration as a stormwater control has included:

• Design criteria for amount of run-off to be infiltrated
• Rate at which infiltration must occur after a storm event
• Pretreatment requirements for run-off prior to discharge to designed infiltration basin
• Stormwater monitoring requirements and standards ("benchmarks") for run-off prior to discharge to designed infiltration basin
• Operation and maintenance requirements.

The draft MPCA infiltration requirements also include several prohibitions, where infiltration can not be used to manage stormwater. These include:

• Certain industrial sectors are prohibited from using infiltration BMPs;
• Certain sensitive areas where groundwater is vulnerable to contamination, including karst areas, and well head protection areas.

Finally, under some circumstances the disposal of stormwater run-off using a designed infiltration system can be further regulated as a Class V Injection Well. This will require further permitting and associated regulation.

For further information contact Caltha LLP at
info@calthacompany.com
or
Caltha LLP Website