City of Champaign


The City of Champaign has enacted Ordinances in order to comply with state and federal environmental regulations. The City of Champaign is the permitting authority for all land disturbing activities and requires the land owner to maintain all on-site stormwater control facilities and all open space areas (e.g. parks or “green” areas) required by the approved stormwater control plan. The City of Champaign will only provide construction permits to projects that establish a plan to manage stormwater runoff occurring during the construction process. Stormwater utility fees will be calculated and collected by the City. The City also offers credits and incentives for properties that engage in and maintain stormwater best management practices. The City of Champaign, under the NPDES program, also has the authority to inspect properties for noncompliance and can issue a notice of violation (NOV) for any deficiency or infraction onsite. Property owners are responsible for the maintenance of any permanent or temporary stormwater facilities or practices located on the property. The City of Champaign has the authority to inspect stormwater facilities and practices in order to ascertain that they properly maintained and functioning.

 

Stormwater Utility Fee

For all other parcels in the City that are not the site of a single family or duplex dwelling, the amount of the stormwater utility fee shall be $5.24 per Equivalent Residential Unit (ERU) or $5.24 per Three thousand four hundred seventy-eight (3,478) square feet of impervious area on the parcel.

Fractional ERUs equal to or less than 0.5 shall be rounded down to the next whole ERU. Fractional ERUs greater than 0.5 shall be rounded up to the next whole ERU. For example, 10,000 square feet of impervious area represents 2.9 ERUs and would be rounded up to 3.0 ERUs for billing purposes.

Fees to qualifying parcels may be adjusted if stormwater utility fee credits are approved by the City for on-site stormwater management.

 

Stormwater Credits & Incentives

Persons subject to the stormwater utility fee shall be eligible to receive a stormwater utility charge credit and/or incentive based upon the requirements of the City of Champaign Stormwater Credit and Incentive Manual.

Any credit allowed against the stormwater utility charge is to be conditioned upon continuing compliance with the City of Champaign Stormwater Credit and Incentive Manual. Proof of compliance as defined in the manual will be required.

Incentives

Incentives are available for any property in the City of Champaign that installs specific types of sustainable stormwater management features. It should be noted that both the credits and incentives programs are mutually exclusive and that credits and incentives will not be awarded to the same property, with the exception of the Private Detention Basin Maintenance Credit which can be earned in conjunction with either credits or incentives. Those properties that are eligible for credits will have to choose between the two programs. This Table summarizes the types of stormwater management features that qualify for incentives and the maximum incentive amounts available.

Maximum Available Stormwater Management Incentives

Incentive Type

Maximum Amount

Rain Garden

$250

Runoff Rate Reduction

$250

Runoff Volume Reduction

$250

Runoff Water Quality

$250

Total Incentive Available

$1,000

Rain Barrel

$25 per barrel

(no maximum limit)

 

The maximum lifetime incentive amount available per property for the combination of rain gardens, rate reduction, volume reduction and water quality items is $1,000. Once a property reaches $1,000 in incentive payments for these items, no more incentives will be issued to the property regardless of the ownership. Rain barrels are not subject to any maximum lifetime incentive amount.

 

Credits

The City of Champaign has adopted a credit program policy that has identified a total of 6 categories of credits. These categories include: 1) private detention maintenance credits; 2) rate reduction credits; 3) volume reduction credits; 4) water quality/BMP credits; 5) direct discharge credits, and 6) education credits. The below table summarizes the credits and the applicable credit limit for each category.

Stormwater Utility Fee Credits

Credit Type

Credit Amount

(For Non-Residential)

Private Detention Basin Maintenance

15% max.

Runoff Rate Reduction

15% max.

Runoff Volume Reduction

15% max.

Runoff Water Quality/NPDES Permit

15% max.

Direct Discharge

50% max.

Education

$5/student

 

Eligibility for Credits and Incentives

The following policies apply to eligibility for participation in the City of Champaign Credit and incentive programs:

a) The incentive program is available for participation by any property in the City of Champaign that is not participating in the rate reduction, volume reduction, water quality, or direct discharge credit programs.

b) Any property whose stormwater runoff discharges to a privately maintained detention basin may be eligible to receive a private detention basin maintenance credit. To qualify the property must participate in the maintenance of the facility and proof must be provided that maintenance is indeed being performed as required by Chapter 23 of the City of Champaign Manual of Practice. Upstream properties do not qualify unless capacity in the detention basin is specifically designed to accommodate their runoff and the upstream property is responsible for its share of the detention basin’s maintenance.

c) Owners of properties other than single family residential or duplex are eligible to apply for rate reduction, volume reduction, or water quality credits for qualifying activities.

d) Credits will not be granted for any stormwater management control built or maintained using funds provided by the City of Champaign.

 

Credit / Incentive Determination

It is the intent of the City to process applications within thirty (30) working days of submittal of a complete and correct application package. Billing adjustments required to implement credits shall be applied retroactively to the date of receipt of the customer’s complete application. A pending application for credit shall not constitute a valid reason for non-payment of the currently assessed stormwater utility fee by the customer. If an application is denied, a letter explaining reason(s) for the denial will be provided to the applicant. The applicant has the right to appeal this decision in accord with the procedures outlined in Article VI of Chapter 29.5 of the City Code.

 

Maintenance Required

All stormwater management facilities require maintenance in order to perform as designed. Stormwater detention facilities are required to be maintained as prescribed in Chapter 23 of the City of Champaign Manual of Practice. Proof of maintenance is required annually in the form of an annual report. Failure to maintain stormwater management facilities will result in the loss of stormwater utility fee credits.

 

Term of Credit

All stormwater utility fee credits must be reapplied for every 5 years. In the case of stormwater detention maintenance credits the owner should consider reapplication coincident with the 5 year cycle of reporting required by Chapter 23 of the City of Champaign Manual of Practice.

 

Indemnification

In consideration for permission to construct, install, or modify a stormwater management facility or BMP, and by nature of applying for a stormwater utility fee credit, the applicant is hereby legally acknowledging and agreeing to the following:

  1. After completion of the construction, modification, or installation by the Owners and approval by the City, the stormwater management facility or BMP shall remain a privately owned and maintained stormwater management facility /BMP, shall not be accepted by the City, and shall not become a part of the maintenance program of the City. All maintenance responsibility and liability shall be and remain with the Owners, their personal representatives, heirs, grantees, successors and assigns.
  2. Owners, their personal representatives, heirs, grantees, successors and assigns shall indemnify and hold harmless the City, its officers agents and employees from any and all claims, actions, causes of action, judgments, damages, losses, costs, and expenses (including attorney's fees) arising out of or resulting from the construction, modification, installation, maintenance, or operation of the stormwater management facility / BMP.
  3. Owners, their personal representatives, heirs, grantees, successors and assigns acknowledge that credits are not perpetual and that both maintenance of stormwater management facilities and annual reporting of maintenance activities may be required in order to maintain all approved credits, and that credits must be re-applied for every 5 years.
  4. This Agreement provides the City and its representatives Right of Entry to inspect and/or monitor the performance of stormwater management facilities.
  5. This Agreement shall run with the real estate upon which the stormwater management facility / BMP has been constructed and shall be binding upon the Owners, their personal representatives, heirs, grantees, successors and assigns so long as the stormwater management facility and/or improvement or any part of it shall be used by them. This Agreement shall be disclosed upon transfer of real estate. At such time as the stormwater management facility / BMP shall cease to be so used, this Agreement shall immediately terminate.

 

Suspended / Terminated Credits

If the terms of the credit are not met, particularly in regard to annual reporting and maintenance when required, the property owner will be notified and will have 30 days to come into compliance before the credit will be terminated. Once a credit is terminated a complete application must be submitted in order to restore the credit.

 

Credit Limit

Credits are limited to a maximum of 50 percent of a property’s total stormwater utility fees.

 

Rainfall Proration

For volume reduction credits where rainfall prorations will be applicable, the following table shall be used:

Rainfall Depth (Inches)

Credit Proration Factor

0.50 to 0.74

50%

0.75 to 0.99

75%

1.00 or more

100%

 

INCENTIVE CRITERIA

Incentives are available for any property in the City of Champaign that installs specific types of sustainable stormwater management features. It should be noted that credits and incentives programs are mutually exclusive and that credits and incentives will not be awarded to the same property. Those properties that are eligible for credits will have to choose between the two programs.

Incentive Application Process

The following process should be followed to submit an application for a stormwater management incentive.

  1. Download current Incentive Application Form from the City website or obtain the form from the City of Champaign Public Works Department (702 Edgebrook Drive).
  2. Prepare Incentive Application Form
  3. Submit form and attachments (if required) to the address on the Incentive Application Form
  4. City will check to insure submittal is complete and notify applicant
  5. City will review application within 30 working days and notify applicant of incentive determination, including identification of deficiencies if the application is not approved
  6. If the incentive is denied applicant may address identified deficiencies and resubmit a revised application
  7. If an incentive is denied applicant may appeal the determination following guidelines in Article VI of Chapter 29.5 of the City Code

Rain Gardens

Rain gardens are shallow depressions planted with native perennial plants that are either located near a downspout or that are in an area that sheds noticeable amounts of rainwater. Rain gardens reduce runoff, absorb pollutants, and sustain some wildlife.

The City will reimburse property owners $250 for a rain garden that has a minimum surface area of 100 square feet and has at least 500 square feet of impervious area draining into it. Smaller rain gardens shall be prorated based on the square footage of the rain garden. The minimum rain garden eligible for an incentive shall be 50 square feet.

The rain garden should be designed with a ponding area to capture and infiltrate the runoff from one inch of rainfall on the contributory impervious area within 24 hours.

The property owner is required to submit their rain garden plan to the City for review and approval. The City will pay the incentive to the property owner after construction has been completed and the construction has been inspected and approved by the City.

There would be only one reimbursement rain garden per property. Rain gardens in excess of 100 square feet are eligible to qualify for volume, rate reduction and water quality incentives. Rain gardens that receive these incentives are not eligible to receive the incentives under this section.

Rain Barrels

Rain barrels are structures designed to intercept and store runoff from rooftops. Typically, a rain barrel is a 55-gallon drum connected to a downspout. The stored water can provide irrigation for a garden or can be released slowly to a lawn.

The City provides an incentive of $25 to the property owner for the purchase of a rain barrel. The incentive payment is made after the property owner provides proof of rain barrel purchase to the City.

There is no limit to the number of rain barrel incentives a property owner can obtain under this program.

Other Incentives

All properties in the City are eligible for incentives for installing and/or implementing activities that provide either a reduction in peak discharge, a reduction in stormwater runoff volume, a water quality benefit, or some combination of the three. The property owner is required to submit a plan to the City for review and approval prior to construction or installation of the stormwater management practice or facility. The amount of the incentive would be 25% of the construction cost for the activity up to a maximum incentive of $250 for each category. The City would pay the incentive to the property owner after construction has been completed and the installation has been inspected and approved by the City. All costs for the construction of the stormwater management feature(s) must be documented and submitted to the City before payment of the incentive.

These incentives could be earned individually, i.e. one $250 maximum incentive for installing a water quality management activity or one $250 maximum incentive for installing a volume reduction management activity. It would also be possible to combine activities, i.e. installing one management activity that accomplishes a combination of rate reduction, volume reduction and/or water quality improvement. In the case of combination, it would be possible to achieve $750 in maximum incentive payment for installing one single stormwater management activity valued at $3,000, if it achieves all three categories. $750 is the maximum incentive amount that a property owner is eligible for under this section.

Other Stormwater Features That Qualify for Incentives

Incentive Type

Category

Permeable Pavement

Peak Discharge/Volume Reduction/Water Quality

Cistern

Volume Reduction

Green Roof

Peak Discharge/Volume Reduction/Water Quality

Bioswale

Peak Discharge/Volume Reduction/Water Quality

Rain Garden

Peak Discharge/Volume Reduction/Water Quality

Detention Basins

Peak Discharge/Volume Reduction/Water Quality

Vegetated Swales

Peak Discharge/Volume Reduction/Water Quality

Manufactured BMPs

Peak Discharge/Volume Reduction/Water Quality

 

These incentives are subject to three rules: 1) the stormwater management feature must capture, store and/or treat a 1-inch rainfall from a minimum of 500 square feet of impervious area; 2) the amount of the incentive is 25% of the construction cost, up to a maximum incentive of $250 per incentive category, and; 3) each property is eligible to receive no more than one incentive disbursement for each of the three categories (Runoff Rate Reduction, Runoff Volume Reduction, and Water Quality Control) in a lifetime.

Eligible construction costs for calculation of the incentive payment must be directly related to the costs associated with the stormwater management feature. Stormwater features constructed for new homes would be eligible for the incentives.

 

CREDIT CRITERIA

The City of Champaign has adopted a credit program policy that has identified a total of 6 categories of credits. These categories include: 1) private detention maintenance credits; 2) rate reduction credits; 3) volume reduction credits; 4) water quality/BMP credits; 5) direct discharge credits, and 6) education credits. In the following sections the credits available to properties in Champaign are discussed, including the specifics of how to apply for the credits.

Credit Application Process

The following process should be followed to submit an application for a stormwater utility fee credit.

  1. Download current credit application forms from City website or obtain the form from the City of Champaign Public Works Department (702 Edgebrook Drive).
  2. Prepare General Credit Application Form
  3. Prepare credit-specific application form(s)
  4. Prepare or locate required site drainage plan showing topography, drainage patterns, and contributing area to each stormwater management structure
  5. Prepare technical calculations required to determine applicability of credit(s)
  6. Obtain appropriate signatures on forms
  7. Submit forms and required attachments to the address on the General Application Form
  8. City will check to insure submittal is complete and notify the applicant
  9. City will review application within 30 working days and notify the applicant of credit determination, including identification of deficiencies if the application is not approved
  10. If credit is denied applicant may address identified deficiencies and resubmit the revised application
  11. If credit is denied applicant may appeal the determination following guidelines in Article VI of Chapter 29.5 of the City Code

The process may vary depending on the type of credit being applied for. Specific criteria are provided in the following sections.

Private Detention Basin Maintenance Credit (Maximum 15%)

Property owners that discharge a portion or all of their impervious area runoff to a private detention basin that was: 1) required by the City’s stormwater management regulations; 2) built to those standards; and 3) are complying with Chapter 23 of the City’s Manual of Practice for Detention Basins Standards for Maintenance and Repair Responsibilities, are eligible for up to a 15 percent credit. The credit will be renewed each year upon receipt of the detention basin annual condition report and its review and approval by the City. The credit will be renewed on the fifth year upon receipt of the professional engineer’s condition report and its review and approval by the City. The 5-year submittal of the professional engineer’s condition report is a requirement of Chapter 23 of the City’s Manual of Practice.

Properties that are in the tributary area of qualifying detention basins and who contribute to the maintenance of the basins are eligible to apply for this credit. For detention basins that accept the direct runoff from subdivision developments that include individual single family residential or duplex properties, the credit must be applied for by a homeowner or lakeowner association on behalf of its members. Individual single family residential or duplex properties may not apply.

Upstream properties may not receive credit unless the detention basin was designed specifically to provide detention for their runoff and unless they participate in the maintenance expense.

Partial credit is not available for incomplete maintenance.

To receive this credit the applicant must provide the following information:

  1. A completed General Credit Application Form
  2. A completed Private Detention Basin Maintenance Credit Application Form
  3. A copy of the most recent maintenance report as required in Chapter 23 of the City’s Manual of Practice
  4. A copy of the site drainage plan with lots and addresses, showing drainage areas tributary to the detention basin
  5. A copy of any calculations that help support and/or determine credit eligibility of the impervious area of the site and of the contributing drainage area

Rate Reduction Credit (Maximum 15%)

A rate reduction credit is available to properties that install and maintain stormwater rate reduction devices that control stormwater flow rates from sites to a level that is lower than what is required by the City stormwater management regulations. This type of credit is typically applied to properties that oversize detention basins to account for offsite upstream stormwater flows that enter the site. The property owner would be required to submit their plan for the rate reduction stormwater management device to the City for review and approval. The property owner’s plan must be prepared and certified by a professional qualified to submit stormwater management plans. A professional engineer registered in the State of Illinois would satisfy this requirement. The rate reduction achieved by the stormwater management device must meet or exceed the requirements of the City’s stormwater management regulations. The rate reduction device can earn up to a maximum credit of 15 percent depending on the reduction of flow rate and the amount of detention storage in excess of that required by the City stormwater management regulations.

The City will apply the credit after the City approved rate reduction plan has been constructed and inspected by the City. Every five years, the City will consider renewal of the credit upon receipt of a report from the property owner prepared by a certified professional indicating the rate reduction stormwater management practice is functioning as designed and is being maintained.

The Rate Reduction Credit is available to all developed properties that install and maintain a stormwater rate reduction device that results in oversizing a detention basin by at least 20 percent over that which is required by the City stormwater management regulations.

To qualify to receive the maximum 15 percent Rate Reduction Credit, the detention basin must have at least 20 percent more volume than is required by the City stormwater management regulations for a 100-year rainfall event. The property owner’s designer must show that the detention basin is properly designed to detain the runoff for the 100-year rainfall event for the entire contributing drainage area, including any offsite areas. To confirm that this criteria was met for an existing detention basin, calculations, based on the criteria in Chapter 23 of the City’s Manual of Practice, must be provided that show that the as-built storage volume of the detention basin is at least 20 percent larger than what was required for the property owner’s property alone. Built out conditions must be assumed for the entire contributing areas.

Prorated credit will be considered for design storms less than the 100-year rainfall event. However, the excess storage volume of the detention basin must be at least 20 percent larger for any design storm to qualify for any credit. Example; a detention basin that has 20 percent more capacity than what is required by the City stormwater management regulations for a 50-year rainfall event would qualify for a 7.5 percent credit.

Rate Reduction Credit Application Process

To receive this credit the applicant must provide the following information:

  1. A completed General Credit Application Form
  2. A completed Rate Reduction Credit Application Form
  3. A copy of the site drainage plan, showing drainage areas tributary to the detention basin
  4. Copies of technical calculations showing the computation of the design capacity of the detention basin
  5. Copies of detention basin modeling output for the appropriate runoff volumes and retention times

Volume Reduction Credit (Maximum 15%)

Volume reduction credits are available for those activities that reduce the total volume of runoff from a property. A volume reduction credit requires the implementation of a stormwater infiltration or reuse practice. Many of these practices are also referred to as rainfall or stormwater harvesting practices, as rather than allowing the rainfall to simply runoff into a drainage system or receiving water body, the rainfall or runoff is intercepted and stored for a beneficial use, such as irrigation of lawns or plantings, or for non-potable uses such as toilet flushing.

Volume reduction practices can earn up to a 15 percent credit, depending on the fraction of the total impervious area served and the equivalent depth of rainwater or runoff that is either infiltrated or reused. The full 15 percent credit will be issued to all volume reduction practices that capture and store a 1-inch rainfall from the entire impervious area present on a property. For volume reduction practices that capture and store less than a 1-inch of rainfall from the entire impervious area on a property, credit will be prorated based on the fraction of rainfall and the fraction of the total impervious area on the property that drains into the volume reduction device.

Volume reduction practices also provide a water quality benefit. A practice designed to capture 1.0 inch of rainfall in Champaign, Illinois will capture almost all of the runoff for 90% of the annual rainfall events, meaning 100% capture of suspended and many dissolved stormwater pollutants for most events, and a significant capture and removal for events exceeding 1.0 inches of rainfall. Therefore, a Volume Reduction Credit in all likelihood will also qualify for at least a partial Water Quality Credit.

Stormwater controls that are constructed with underdrains do not qualify for this credit.

Stormwater controls must be drained within 72 hours to qualify for a Volume Reduction Credit.

The following sections define a variety of rainfall harvesting and reuse techniques that would qualify for a Volume Reduction Credit. The City is willing to consider other techniques not listed here for Volume Reduction Credits.

1) Cisterns

A cistern is a watertight receptacle for holding rainwater. Cisterns range in capacity from a few hundred gallons to thousands of gallons, effectively forming covered reservoirs. The water in cisterns can be used for irrigation or other types of reuse and infiltration practices. Cisterns are typically gravity fed and capture runoff from surfaces at the same level or higher than the storage, typically from rooftops. The Volume Reduction Credit for a cistern requires that the cistern capture and store 1 inch of rainfall from the impervious area contributing runoff. The credit may be prorated based on the fraction of the total impervious area of the property that provides water to the cistern and the fraction of rainfall depth that can be stored. The volume reduction plan must explain how the captured rainwater will be used so as to empty the stored water within 72 hours.

2) Green Roofs

A green roof is a roof of a building that is partially or completely covered with vegetation and a growing medium, planted over a waterproof membrane.

Green roofs serve several purposes for a building, such as absorbing rainwater, providing insulation, creating a habitat for wildlife, and helping to lower urban air temperatures and combat the heat island effect. There are two types of green roofs: intensive roofs, which are thicker and can support a wider variety of plants but are heavier and require more maintenance, and extensive roofs, which are covered in a light layer of vegetation and are lighter than an intensive green roof.

The Volume Reduction Credit for a green roof requires the roof to capture and infiltrate 1 inch of rainfall. The credit may be prorated based on the fraction of 1 inch of rainfall that is retained and on the fraction of the total impervious area of the property that the green roof represents

3) Permeable Pavement

Pervious and permeable pavements are a range of materials and techniques for paving roads, parking lots and pavements that allow the movement of water and air around the paving material. Although some porous paving materials appear nearly indistinguishable from traditional nonporous materials, their environmental effects are qualitatively different. Whether pervious concrete, porous asphalt, paving stones or bricks, all these pervious materials allow precipitation to percolate through areas that would traditionally be impervious.

To qualify for the Volume Reduction Credit the impervious area calculations must include the area of the Permeable Pavement surface in the storage volume computations, and the storage must be based on 1.0 inches of rainfall on the impervious areas.

The credit may be prorated based on the fraction of 1 inch of rainfall that moves through the pavement and on the fraction of the total impervious area of the property.

Volume Reduction Credit Application Process

To qualify for the Volume Reduction Credit, the property owner would need to submit their volume reduction plan to the City for review and approval. The property owner’s plan must be prepared and certified by a professional qualified to submit stormwater management plans. A professional engineer registered in the State of Illinois would satisfy this requirement. The City would apply the credit after the approved volume reduction plan has been constructed and inspected by the City. Every five years, the City would consider renewal of the credit upon receipt of a report from the property owner prepared by a certified professional indicating the volume reduction stormwater management practice is functioning as designed and is being maintained properly. Credit renewal would take place after the City has reviewed and approved the report.

To receive this credit the applicant must provide the following information:

  1. A completed General Credit Application Form
  2. A completed Volume Reduction Credit Application Form
  3. A copy of the site drainage plan, showing drainage areas tributary to the volume reduction control(s)
  4. A copy of calculations of the impervious areas of the site and of the contributing drainage area to each volume reduction control
  5. Copies of technical calculations showing the computation of the design capacity of the volume reduction control(s)
  6. Design drawings

Water Quality and NPDES Permit Credit (Maximum 15%)

Properties that provide measures to improve the quality of stormwater runoff that leaves the property may be eligible to receive a Water Quality Credit. For those properties that are granted either a rate or volume reduction credit, the Water Quality Credit may be added to those credits.

Credit is also available to industrial sites or other municipalities that are required to have a NPDES permit that is issued by the Illinois Environmental Protection Agency.

Water Quality / BMP Credit (Maximum 10%)

A credit may be provided to those applicants’ properties that discharge a portion or all of their impervious area runoff to structural or non-structural best management practices (BMPs). The water quality credit will be granted if the applicant can demonstrate that the BMPs are designed to provide a minimum of 75 percent reduction in total suspended solids (TSS) in the stormwater runoff, as measured on an annual basis. Engineering calculations and, if applicable, vendor specifications for manufactured BMPs shall be submitted to demonstrate the minimum 75 percent TSS removal efficiency of the BMPs.

The maximum amount of Water Quality/BMP credit that will be provided is 10 percent. The final credit can be prorated based on the fraction of the total impervious surfaces on site that flows through the BMP.

To qualify for the Water Quality Credit, the property owner is required to submit their water quality plan to the City for review and approval. The property owner’s plan must be prepared and certified by a professional qualified to submit stormwater management plans. A professional engineer registered in the State of Illinois satisfies this requirement. The City will apply the credit after the approved water quality plan has been constructed and inspected by the City. Every five years the City will consider renewal of the credit upon receipt of a report from the property owner prepared by a certified professional indicating the water quality stormwater management practice is functioning as designed and is being maintained properly.

Credit renewal will take place after the City has reviewed and approved the report.

The following sections define a variety of BMP’s that qualify for Water Quality Credits. The City is willing to consider other techniques that are not listed that can demonstrate the ability to achieve 75 percent total suspended solids removal from the runoff.

a) Water Quality Detention Basins. Water quality detention basins are extended wet bottom detention basins that are designed with two control volumes; one control volume is for flood management for the 100-year event as required by City stormwater management regulations and Chapter 23 of the City’s Manual of Practice, and the other is the water quality volume that is used to treat stormwater runoff prior to discharge from the detention basin. Water quality detention basins are efficient at sediment removal and for that reason their design often includes a pretreatment area (forebay) or device that promotes sediment removal in an area of the detention basin that can easily be cleaned. The water quality storage volume is typically computed based on the volume of runoff generated by the “first flush” depth of runoff, assumed to be 1.0 inches in Champaign. The water quality, or first flush volume can be computed by the following equation

Vff = 3,630 * C * A

Where:

Vff = First flush volume, post-development (in cubic feet)

C = Post-development runoff coefficient

A = Drainage area tributary to detention basin (in acres)

In order to qualify for the maximum 10 percent credit, water quality detention basins must be designed to the Vff volume for the entire property and must demonstrate a 75 percent removal of TSS. Partial credits are available based on the fraction of total impervious area on the property served by the detention basin.

b) Vegetated swales. Vegetated swales, or “bioswales”, are landscape elements designed to remove silt and pollution from surface runoff. They consist of a swaled drainage course with gently sloped sides and filled with vegetation, compost and/or riprap. The water's flow path, along with the wide and shallow ditch, is designed to maximize the time water spends in the swale, which aids the trapping of pollutants and silt. Biological factors also contribute to the breakdown of certain pollutants. A common application of vegetated swales is around parking lots, where substantial automotive pollution is collected by the paving and then flushed by rain. The bioswale, or other type of biofilter, wraps around the parking lot and treats the runoff before releasing it to the storm sewer.

In order to qualify for the maximum 10 percent credit, vegetated swales must be designed to collect and treat a 1-inch rainfall from at least 20 percent of the total impervious area on a property. Partial credits are available based on the fraction of total impervious area on the property served by the vegetated swales.

c) Manufactured BMPs. Manufactured BMPs are a family of BMPs that can be installed as standalone water quality treatments or can be used in conjunction with detention basins to pre-treat the inflow. Some of these devices are considered hydro-dynamic separation units, others use micro-screening techniques, and others provide biofiltration in a closed environment. Manufactured BMPs qualify for the Water Quality Credit if properly sized to remove 75 percent TSS.

In order to qualify for the maximum 10 percent credit, a manufactured BMP must be designed to collect and treat a 1-inch rainfall from at least 20 percent of the total impervious area on a property. Partial credits are available based on the fraction of total impervious area on the property served by the manufactured BMP.

To receive this credit the applicant must provide the following information:

  1. A completed General Credit Application Form
  2. A completed Water Quality Application Form
  3. A copy of the site drainage plan, showing drainage areas tributary to the water quality BMP
  4. Copies of technical calculations showing the computation of the water quality storage required
  5. A copy of calculations of the impervious areas of the site and of the contributing drainage area
  6. Copies of detention basin modeling output for the appropriate runoff volumes and retention times for water quality detention basins
  7. Design drawings if retrofit or new construction

NPDES Permit Credit (5%)

This credit will apply only to property owners who are subject to either an industrial or municipal NPDES Stormwater Permit issued by the Illinois Environmental Protection Agency. This credit is conditional upon the proof of permit coverage and continuing compliance. The applicant shall submit her/his most recent annual site compliance inspection/audit update to prove compliance with an industrial NPDES stormwater permit, or the last annual report for a municipal NPDES stormwater permit in order to remain eligible for this credit. Similar information will be submitted annually in order to continue to receive the credit.

This credit will be in the amount of 5 percent for the entire area covered under the NPDES permit inside the City of Champaign corporate limits.

To receive this credit the applicant must provide the following information:

  1. A completed General Credit Application Form
  2. A completed NPDES Credit Form
  3. A copy of the permittee’s Notice of Intent
  4. A copy of the permittee’s latest annual site compliance report (industrial permit) or annual report (municipal permit)

Direct Discharge Credit (up to 50%)

Properties that discharge directly to stormwater facilities or conveyances that are not maintained by the City and that do not eventually re-enter City-maintained drainage systems or streams, exert a lower demand for service on the City’s stormwater program than do properties whose runoff must be accommodated by drainage system capacity, planning, and floodplain management. In recognition of that reduction in demand, the City will provide up to a 50 percent credit to those qualifying properties.

Credit amounts are based on the amount of area that does not directly discharge into City stormwater infrastructure. For properties that partially drain into City infrastructure, a prorated credit amount will be determined based the area that does not directly discharge into City stormwater infrastructure.

To receive this credit, the applicant must submit site plans for the property demonstrating which portion(s) of the parcel qualify for this credit and the credit will be prorated accordingly.

To receive this credit the applicant must provide the following information:

  1. A completed General Credit Application Form
  2. A completed Direct Discharge Credit Application Form
  3. A copy of the site drainage plan, showing delineated drainage areas that discharge to receiving waters outside the City of Campaign and all of the impervious area on the property
  4. A copy of calculations of the impervious areas of the entire property and of the non-contributing drainage areas

 

LINKS:

Champaign Stormwater Utility Fee Credit and Incentive Manual

Private Detention Basin Checklist and Chapter 23 Standards