March 14, – 5:30 p.m.

March 14, 2011 Meeting Agenda 1. Minutes (February 14, 2011) 2. Member Inquiries / Staff Follow-up 3. Stormwater Management – Revenue Plan 4. Public Participation 5. Next Meeting (April 11, 2011) 6. Adjourn

Stormwater Utility Fee Advisory Technical Committee Meeting March 14, 2011 Agenda Item 3 Revenue Plan Rate Structure

Background Information Revenue Plan defines how the costs of the Expenditure Plan will be allocated Rate structure contains the specifics of the plan Program Costs (from Expenditure Plan) - Other Revenues(various fees, interest, etc) +Revenue Reductions(bad debt, credits, etc) =Revenue Needed from Fee ÷ Rate Base(total number of billing units) =Rate

Stormwater Utility Fee Advisory Technical Committee Meeting March 14, 2011 Agenda Item 3 Rate Structure Base Structure

Impacts of Development on Runoff

Impact of development on runoff peak Rational Formula Q = C  i  A whereQ=discharge rate C=runoff coefficient i=rainfall intensity A=drainage area “C” increases with increasing intensity of development (imperviousness)

Impact of development on runoff volume Simple Method V = P  Rv  A / 12 whereV=runoff volume P=rainfall depth A=drainage area Rv=runoff coefficient =  i i=impervious percentage

Impact of development on runoff quality Simple Method L = V  EMC L = (P  Rv  A / 12)  EMC whereL=pollutant load V=runoff volume EMC=event mean concentration P=rainfall depth Rv=runoff coefficient =  i i=impervious percentage

Imperviousness as a rate method Imperviousness is utilized in hydrology as the measuring stick for intensity of development Multiple ways to include imperviousness in fee calculations:  Straight imperviousness (actual or incremental blocks)  Equivalent Runoff Units, ERUs (single family flat rate)  Impervious plus gross area  Impervious plus pervious area  Intensity of development Each method has pros and cons

Rate Bases Imperviousness is the only physical parameter per parcel Direct correlation to runoff and thus to demand Easily measured and verified Impervious Area

Rate Bases Compound rate structure  Imperviousness for development  Gross area component for entire property Applies some costs to undeveloped properties Can set minimum threshold for billing Impervious plus Gross Area

Rate Bases Based on the runoff potential of impervious and pervious areas Directly compute billing units per parcel Can apply program costs to undeveloped properties Impervious Plus Pervious Area (Effective Hydraulic Area)

Rate Bases IODLand Use Parking Commercial Institutional Multi-Family Single Family - small lot Single Family - large lot Vacant Utilizes the average runoff potential by land use  Gross area  Land use  IOD factor Directly compute billing units per parcel Typically not accurate enough for billing Increasing Intensity Intensity of Development

How A Fee Is Calculated Significant aspects of rate bases Single family residential  Typically flat rates  Some use tiers to add equity  Some (very few) measure every parcel  Determines (typically) the base rate unit Other parcels  Measure impervious area and compute billing units

How A Fee Is Calculated Non-single family = 10,000 square feet impervious = 3.33 ERUs - credit Impervious Only (Equivalent Residential Unit, ERU) Quarter acre lots 1 ERU = 3,000 square feet of impervious area Single family residential = 3,000 sq ft impervious = 1 ERU

How A Fee Is Calculated Non-single family = 10,000 square feet impervious = 3.33 IAUs GAU - credit Impervious Plus Gross Area Quarter acre lots IAU = 3,000 sq ft impervious area GAU = 1 acre of pervious area Single family residential = 3,000 sq ft impervious = 1 IAU GAU

How A Fee Is Calculated Non-single family = 10,000 square feet impervious = – credit = – credit Impervious Plus Pervious Area (Effective Hydraulic Area, EHA) Quarter acre lots EHA = 95% of impervious area + 10% of pervious area Single family residential = 3,000 sq ft impervious = units = units

Rate Base Discussion Do you have questions / comments about any of the rate base concepts? What did you like / not like about the various methods and their approaches? Impervious only Impervious plus gross area Impervious plus pervious area Intensity of development

Stormwater Utility Fee Advisory Technical Committee Meeting March 14, 2011 Agenda Item 3 Rate Structure Residential Rate Simplifiers

Imperviousness in Champaign Imperviousness is a significant part of all stormwater rate structures For the initial phase of the project an estimate of total imperviousness was needed: Identified primary land uses Determined the statistically significant sample sizes for each land use Digitized the appropriate number of samples for each Estimated rate base size based on the product of gross area and measured intensity of development by land use

Imperviousness by Land Use Land Use No. of Parcels Gross Area Impervious % Impervious Area Single Family 18,050167,040,210 62,777,900 Duplex 3172,804,024 1,102,526 Multi-Family 82419,471,79851% 12,250,300 Condo 3332,281,49766% 1,514,686 Industrial 627,347,75468% 4,973,695 Commercial 1,811108,411,64571% 76,636,192 Churches 1496,449,73553% 3,437,064 Government 75765,589,69532% 20,785,374 University 16024,825,20339% 9,785,206 Misc 20425,202,97532% 1,337,392 Agriculture 7971,417,6171% 857,011 Total Area 22,746500,842,152195,457,346 Approximate Areas in Square Feet

”Bundling” Imperviousness Issue: How do you bill the proposed $2.25M (or $3.21M) annual program cost? Billing per square foot of impervious area (195M) results in a fee of $ / sq ft / yr (not modeled) and thousands of units to be billed per ratepayer Other utilities “bundle” the units of service Electric utilities measure in kilowatt hours Water utilities sell water in thousands of gallons Imperviousness is typically “bundled” in one of two ways: In increments of 500 or 1000 square feet In “equivalent” units, such as based on the average imperviousness on a single family residential property Numbers are Approximate

”Bundling” Imperviousness Land Use Impervious Area* 500 Sq Ft Units 1000 Sq Ft Units 3478 Sq Ft Units Single Family 62,777, ,556 62,778 18,050 Duplex 1,102,526 2,205 1, Multi-Family 12,250,300 24,501 12,250 3,522 Condo 1,514,686 3,029 1, Industrial 4,973,695 9,947 4,974 1,430 Commercial 76,636, ,272 76,636 22,035 Churches 3,437,064 6,874 3, Government 20,785,374 41,571 20,785 5,976 University 9,785,206 19,570 9,785 2,816 Misc 1,337,392 2,675 1, Agriculture 857,011 1, Total Rate Base 195,457,346390,915195,45756,201 *Approximate Area in Square Feet

”Bundling” Imperviousness Therefore, $ / sq ft / yr could be billed as: $ 5.75 / 500 sq ft / yr $0.44 / 500 sq ft / mo $11.50 / 1000 sq ft / yr $0.88 / 1000 sq ft / mo $40.00 / 3478 sq ft / yr $3.33 / 3478 sq ft / mo The number of billing units for single family residential properties under a flat rate method would be: 7.0 units at 500 sq ft bundles 3.5 units at 1000 sq ft bundles 1 unit at 3478 sq ft bundles, or 1 equivalent residential unit (ERU) Numbers are Approximate

Single Family Imperviousness

Residential Rate Simplifier Is there a need to further refine the billing within the single family residential properties? Why some communities do add detail; decreased fees for less imperviousness increased fees for more imperviousness Illinois communities with tiered single family rates: Bloomington, Moline, Rock Island

Residential Rate Simplifier Is there a need to further refine the billing within the single family residential properties? Why some communities do not add detail; increased cost of master account file creation increased cost of master account file maintenance increased uncertainty in account calculation variations within flat rate typically low (± $1.00/mo) Illinois communities with one rate for all single family: Morton, Normal, Highland Park

Questions?