APPENDIX C: STORMWATER MANAGEMENT DESIGN CRITERIA

TABLE C-1 - RATIONAL METHOD RUNOFF COEFFICIENTS

Hydraulic Soil Group	Storm	A			B			C			D
Slope Range	≥	0-2%	2-6%	+6%	0-2%	2-6%	+6%	0-2%	2-6%	+6%	0-2%	2-6%	+6%
Cultivated Land	<25yr	0.08	0.13	0.16	0.11	0.15	0.21	0.14	0.19	0.26	0.18	0.23	0.31
	≥25yr	0.14	0.08	0.22	0.16	0.21	0.28	0.2	0.25	0.34	0.24	0.29	0.41
Pasture	<25yr	0.12	0.2	0.3	0.18	0.28	0.37	0.24	0.34	0.44	0.3	0.4	0.5
	≥25yr	0.15	0.25	0.37	0.23	0.34	0.45	0.3	0.42	0.52	0.37	0.5	0.62
Meadow	<25yr	0.10	0.16	0.25	0.14	0.22	0.3	0.2	0.28	0.36	0.24	0.3	0.4
	≥25yr	0.14	0.22	0.3	0.2	0.28	0.37	0.26	0.35	0.44	0.3	0.4	0.5
Forest	<25yr	0.05	0.08	0,11	0.08	0,11	0.14	0.1	0,13	0.16	0.12	0.16	0.2
	≥25yr	0.08	0.11	0.14	0.1	0.14	0.18	0.12	0.16	0.2	0.15	0.2	0.25
Residential 1/8 Acre	<25yr	0.25	0.28	0.31	0.27	0.3	0.35	0.3	0.33	0.38	0:33	0.36	0.42
	≥25yr	0.33	0.37	0.4	0.35	0.39	0.44	0.38	0.42	0.49	0.41	0.45	0.54
1/4 Acre	<25yr	0.22	0.26	0.29	0.24	0.29	0.33	0.27	0.31	0.36	0.3	0.34	0.4
	≥25yr	0.3	0.34	0.37	0.33	0.37	0.42	0.36	0.4	0.47	0.38	0.42	0.52
1/3 Acre	<25yr	0.19	0.23	0.26	0.22	0.26	0.3	0.25	0.29	0.34	0.28	0.32	0.39
	≥25yr	0.28	0.32	0.35	0.3	0.35	0.39	0.33	0.38	0.45	0.36	0.4	0.5
1/2 Acre	<25yr	0.16	0.2	0.24	0.19	0.23	0.28	0.22	0.27	0.32	0,26	0.3	0.37
	≥25yr	0.25	0.29	0.32	0.28	0.32	0.36	0.31	0.35	0.42	0.34	0.38	0.48
1 Acre	<25yr	0.14	0.19	0.22	0.17	0.21	0.26	0.2	0.25	0.31	0.24	0.29	0.35
	≥25yr	0.22	0.26	0.29	0.24	0.28	0.34	0.28	0.32	0.4	0.31	0.35	0.46
Industrial	<25yr	0.67	0.68	0.68	0.68	0.68	0.69	0.68	0.69	0.69	0.69	0.69	0.7
	≥25yr	0.85	0.85	0.86	0.85	0.86	0.86	0.86	0.86	0.87	0.86	0.86	0.88
Commercial	<25yr	0.71	0.71	0.72	0.71	0.72	0.72	0.72	0.72	0.72	0.72	0.72	0.72
	≥25yr	0.88	0.88	0.89	0.89	0.89	0.89	0.89	0.89	0.9	0.89	0.89	0.9
Streets	<25yr	0.7	0.71	0.72	0.71	0.72	0.74	0.72	0.73	0.76	0.73	0.75	0.78
	≥25yr	0.76	0.77	0.79	0.8	0.82	0.84	0.84	0.85	0.89	0.89	0.91	0.95
Open Space	<25yr	0.05	0.1	0.14	0.08	0.13	0.19	0.12	0.17	0.24	0.16	0.21	0.28
	≥25yr	0.11	: 0.16	0.2	0.14	0.19	0.26	0.18	0.23’	0.32	0.22	0.27	0.39
Parking or Impervious	<25yr	0.85	0,86	0.87	0.85	0.86	0.87	0.85	0.86,	0.87	0.85	0.86	0.87
	≥25yr	0.95	0.96	0.97	0.95	0.96	0.97	0.95	0.96	0.97	0.95	0.96	0.97

 

Source: Rawls, W.J., S.L. Long, and R.H. McCuen, 1981. Comparison of Urban Flood Frequency Procedures. Preliminary Draft Report prepared for the Soil Conservation Service, Beitsville, Maryland.

For simplification, a designer may use 0.3 for all pervious areas and 0.95 for all impervious areas.

TABLE C-2 - RUNOFF CURVE NUMBERS (FROM NRCS (SCS) TR-55)

Runoff Curve Numbers for Urban Areas
Cover Description			Curve Numbers for Hydrologic Soil Groups
Cover Type and Hydrologic Condition		Average Percent Impervious Area	A	B	C	D
Fully Developed Urban Areas (Vegetation Established)
Open Space (lawns, parks, golf courses, etc):
Poor Condition (grass cover < 50%)			68	79	86	89
Fair Condition (grass cover 50% to 75%)			49	69	79	84
Good Condition (grass cover > 75%)			39	61	74	80
Impervious Areas:
Paved Parking Lots, Roofs, Driveways, and the like			98	98	98	98
Streets and Roads:
Paved: Curbed and Storm Sewers			98	98	98	98
Paved: Open Ditches			83	89	92	93
Gravel			76	85	89	91
Dirt			72	82	87	89
Urban Districts:
Commercial and Business		85%	89	92	94	95
Industrial		72%	81	88	91	93
Residential Districts by Average Lot Size:
1/8 Acres or less		65%	77	85	90	92
1/4 Acre		38%	61	75	83	87
1/3 Acre		30%	57	72	81	86
1/2 Acre		25%	54	70	80	85
1 Acre		20%	51	68	79	84
2 Acres		12%	46	65	77	82
Fallow	Bare Soil	—	77	86	91	94
	Crop Residue Cover (CR)	Poor	76	85	90	93
		Good	74	83	88	90
Row Crops	Straight Row (SR)	Poor	72	81	88	91
		Good	67	78	85	89
	SR + CR	Poor	71	80	87	90
		Good	64	75	82	85
	Contoured (C)	Poor	70	79	84	88
		Good	65	75	82	86
	C + CR	Poor	69	78	83	87
		Good	64	74	81	85
	Contoured and Terraced (C&T)	Poor	66	74	80	82
		Good	62	71	78	81
	C&T + CR	Poor	65	73	79	81
		Good	61	70	77	80
Small Grain	SR	Poor	65	76	84	88
		Good	63	75	83	87
	SR + CR	Poor	64	75	83	86
		Good	60	72	80	84
	C	Poor	63	74	82	85
		Good	61	73	81	84
	C + CR	Poor	62	73	81	84
		Good	60	72	80	83
	C&T	Poor	61	72	79	82
		Good	59	70	78	81
	C&T + CR	Poor	60	71	78	81
		Good	58	69	77	80
Close Seeded or Broadcast Legumes Or Rotation Meadow	SR	Poor	66	77	85	89
		Good	58	72	81	85
	C	Poor	64	75	83	85
		Good	55	69	78	83
	C&T	Poor	63	73	80	83
		Good	51	67	76	80
Runoff Curve Numbers for Other Agricultural Lands
Pasture, Grassland, or Range - Continuous Forage for Grazing		Poor	68	79	86	89
		Fair	49	69	79	84
		Good	39	61	74	80
Meadow - Continuous Grass, Protected from Grazing and Generally Mowed for Hay		-	30	58	71	78
Woods - Grass Combination (orchard or tree farm)		Poor	57	73	82	86
		Fair	43	65	76	82
		Good	32	58	72	79
Woods		Poor	45	66	77	83
		Fair	36	60	73	79
		Good	30	55	70	77
Farmsteads - Buildings, Lanes, Driveways and Surrounding Lots.		-	59	74	82	86

 

(Ord. 1508, passed 12-20-2010)

APPENDIX D: REVIEW FEE REIMBURSEMENT AGREEMENT

   THIS AGREEMENT MUST BE COMPLETED AND SIGNED BY THE DEVELOPER/APPLICANT PRIOR TO SUBMISSION OF THE SUBDIVISION/LAND DEVELOPMENT APPLICATION AND PLANS, SKETCH PLANS, CONDITIONAL USE APPLICATIONS OR ANY OTHER SUBMISSION WHICH REQUIRES MUNICIPAL CONSULTANT REVIEW.

REVIEW FEE REIMBURSEMENT AGREEMENT

THIS AGREEMENT, made and entered into this         day of                          , 20        , by and between                                        , (hereinafter the “Landowner”), and                                       , Erie County, Pennsylvania, (hereinafter “City of Corry”);

WITNESSETH

   WHEREAS, the Landowner is the owner of certain real property as recorded by deed in the land records of Erie County, Pennsylvania, Deed Book            at Page           , (hereinafter “Property”).

   WHEREAS, the Landowner is proceeding to build and develop the Property; and

   WHEREAS, the Landowner has submitted a SWM Site Plan for review and approval by the City of Corry (hereinafter referred to as the “Plan”) for the property identified herein; and

   WHEREAS, the Developer has requested and/or required the City of Corry approval and/or review of its proposed plans, and the City of Corry is willing to authorize its professional consultants to review said Plan and/or proposal upon execution of this agreement, and upon deposit of an escrow account according to the current Fee Schedule.

   NOW, THEREFORE, in consideration of the foregoing promises, the mutual covenants contained herein, and the following terms and conditions, the parties hereto agree as follows:

   1.   The Landowner and City of Corry hereby authorize and direct the City of Corry’s engineer or professional consultants, as defined at Section 107 of the Pennsylvania Municipalities Planning Code (53 P.S. §§ 10101 et seq.) to review Landowner’s plans or proposals to use its property, and to make such recommendations and specifications as may be necessary with respect to such plans in accordance with all applicable City of Corry ordinances, and State and Federal rules and regulations.

   2.   The Landowner and City of Corry acknowledge that the City of Corry will incur costs and fees relating to the review of Landowner’s plans by its City Engineer or professional consultants, and Landowner agrees to pay and/or reimburse the City of Corry for such costs in accordance with this agreement.

   3.   The Landowner shall pay the City of Corry or professional consultant’s charges and fees for the following: (a) review of any and all Stormwater Management Plans, studies, or other correspondence relating to the Landowners submission; (b) attendance at any and all meetings relating to Landowner’s plan; (c) preparation of any reports, legal documents, or other correspondence relating to Landowner’s plan or proposal; (d) administrative cost and incurred expenses relating to the administration of this agreement and (e) Professional Consultant’s fees associated with construction activities. It is understood by the execution of this agreement that the Landowner specifically accepts the Fee Schedule currently in effect in the City of Corry.

   4.   The Landowner hereby agrees to deposit with the City of Corry the sum of                   Dollars ($                     ), payable as cash in U.S. Dollars or check drawn on a Pennsylvania bank, as security for the payment of all costs and expenses, charges and fees as set forth in Paragraph 3 above, upon execution of this agreement, which shall be held in a noninterest-bearing account by the City of Corry. In the event that the above deposited escrow fund shall fall below fifty percent (50%) of the original deposit, the Landowner shall immediately, upon receipt of written notice from the City of Corry or its agent(s), deposit sums with the City of Corry necessary to replenish the account to its original balance. In the event that this is insufficient to pay current City of Corry incurred expenses. Landowner agrees to pay the total amount currently due for City of Corry incurred expenses without delay in addition to re-establishing the base escrow account balance. The City of Corry will use its best efforts to advise the Landowner of the impending likelihood that its costs have exceeded the required escrow account sums as described above.

   5.   Landowner and City of Corry agree that upon completion of the City of Corry’s review of Landowner’s plan or proposal, all unused portions of the escrow account as described above shall be returned to the applicant upon written request to the City of Corry.

   6.   Landowner and City of Corry acknowledge that the Ordinance and appropriate fee schedules require Landowner to pay the City’s Engineer or professional consultant fees relating to this plan or project, and in the even that Landowner fails to provide sufficient funds in the above-described revolving escrow account upon fifteen (15) days written notice to the Landowner or make the initial deposit payment described above within five (5) days of the date of this agreement. Landowner shall be in default of this agreement and in violation of the above Sections of Ordinance. In the event of Landowner’s default as described above, the City of Corry may refuse to issue any permit or grant any approval necessary to further improve or develop the subject site until such time as the terms of this Agreement are strictly met by Landowner. Moreover, final approval or further review may be denied or delayed until such time as the terms of this agreement are strictly met by Landowner.

   7.   Landowner and the City of Corry further agree that all fees or costs arising out of this Agreement shall be paid prior to the issuance of any permit, occupancy or otherwise, for the use, improvement or construction of the buildings as proposed on the Landowner’s plan. The Landowner agrees and acknowledges that no permit, occupancy or otherwise, or recordable plans, shall be released by the City of Corry until all outstanding professional consultant fees and costs are paid to the City of Corry, and provided that the Landowner is not in default under this agreement.

   8.   The Landowner may at any time terminate all further obligations under this Agreement by giving fifteen (15) days written notice to the City of Corry that it does not desire to proceed with the development as set forth on the plan and upon receipt of such written notice by the Landowner to the City of Corry, the Landowner shall be liable to the City of Corry for its costs and expenses incurred to the date and time of its receipt of the notice, plus the applicable administrative costs and expenses as outlined in Paragraph 3 above.

   9.   The Landowner and the City of Corry further agree that the City of Corry shall have the right and privilege to sue the Landowner or then property owner in assumpsit for reimbursement or to lien the property or both, in its sole discretion, for any expense in excess of the then current balance of funds on deposit with the City of Corry in accordance with this agreement incurred by the City of Corry by reason of any review, supervision and inspection of Landowner’s project by its professionals including, but not limited to, the City Engineer and City Solicitor. The City of Corry’s election of its remedies under this paragraph shall not constitute a waiver of any other remedies the City of Corry may have.

   10.   The Landowner and the City of Corry acknowledge that this agreement represents their full understanding as to the City of Corry’s reimbursement for professional or consultant services.

   11.   This agreement shall be binding on and insure to the benefit of the successors and assigns of Landowner. The City of Corry shall receive thirty (30) days’ advance written notice from Landowner of any proposed assignment of Landowner’s rights and responsibilities under this Agreement.

ATTEST:

WITNESS the following signatures and seals:

(SEAL)                                    For the City of Corry:

                                       For the Landowner:

ATTEST:

                                             (City, Borough, Township)

County of Erie, Pennsylvania

I                           , a Notary Public in and for the County and State aforesaid, whose commission expires on the                       day of                         , 20            , do hereby certify that                                     whose name(s) is/are signed to the foregoing Agreement bearing date of the                              day of                     , 20               , has acknowledged the same before me in my said County and State.

GIVEN UNDER MY HAND THIS                           day of                          , 20                       .

NOTARY PUBLIC                     (SEAL)

(Ord. 1508, passed 12-20-2010)

APPENDIX E: SMALL PROJECT SWM PLAN APPLICATION

   Per the City of Corry’s Stormwater Management Act, 32 P.S. §§ 680.1 et seq., a stormwater management plan is required whenever more than 2,500 square feet of impervious surface are proposed. Impervious surfaces are areas that prevent the infiltration of water into the ground and shall include, but not be limited to, roofs, patios, garages, storage sheds and similar structures, and any new streets or sidewalks.

To Calculate Impervious Surfaces Please Complete This Table
Surface Type	Length (feet)	X	Width (feet)	=	Proposed Impervious Area
Building (area per downspout)		X		=
		X		=
		X		=
		X		=
Driveway		X		=
		X		=
		X		=
Parking Areas		X		=
		X		=
		X		=
Patios/Walks		X		=
		X		=
		X		=
		X		=
Other		X		=
		X		=
		X		=
Total Impervious Surface Area to be managed (sum of all areas)

 

   If the Total Impervious Surface Area is LESS THAN 2,500 Square Feet, please read, acknowledge and sign below.

   If the Total Impervious Surface Area EXCEEDS 2,500 Square Feet, complete the remainder of the Application.

   Based Upon the information you hove provided a Stormwater Management Plan IS NOT required for this regulated activity. The City of Corry may request additional information and/or SWM for any reason.

   Property Owner Acknowledges that submission of inaccurate information may result in a stop work order or permit revocation. Acknowledgement of such is by signature below. I declare that I am the owner or owner’s legal representative. I further acknowledge that the information provided is accurate and employees of [municipality] are granted access to the above described property for review and inspection as may be required.

                                                                       Owner         Date:                                    

CREDITS

Credit 1: DISCONNECTION OF IMPERVIOUS AREA

   When runoff from impervious areas is directed to a pervious area that allows for infiltration, filtration, and increased time of concentration, all or parts of the impervious areas may qualify as Disconnected Impervious Area (DIA). Using the criteria below, determine the portion of the impervious area that can be excluded from the calculation of total impervious area.

Criteria: An impervious area is considered to be completely or partially disconnected if it meets the requirements listed below

   (A)   Rooftop area draining to a downspout is 500 sf

   (B)   Paved area draining to a discharge is 1,000 sf

   (C)   Flow path of paved impervious area is not more than 75’

   (D)   Soil at discharge is not designated as hydrologic soil group “D”

   (E)   Flow path at discharge area has a positive slope of 5%

   (F)   Gravel strip or other spreading device is required at paved discharges.

 

Length of Pervious Flow Path from discharge point *	DIA Credit Factor
0-14	1.0
15-29	0.8
30-44	0.6
45-59	0.4
60-74	0.2
75 or more	0

 

Flow path cannot include impervious surfaces and must be at least 15 feet from any impervious surfaces.

Calculate DIA Credit and Required Capture Volume
Surface Type	Proposed Impervious Area (from previous sheet)	X	DIA Credit Factor	=	Impervious Area to be managed	/		=	Required Capture Volume (ft3)
Building (area per downspout)		X		=		/	6	=
		X		=		/	6	=
		X		=		/	6	=
		X		=		/	6	=
Driveway		X		=		/	6	=
		X		=		/	6	=
		X		=		/	6	=
Parking Areas		X		=		/	6	=
		X		=		/	6	=
		X		=		/	6	=
Patios/Walks		X		=		/	6	=
		X		=		/	6	=
		X		=		/	6	=
		X		=		/	6	=
Other		X		=		/	6	=
		X		=		/	6	=
		X		=		/	6	=
Total Req’d Capture Volume

 

Credit 2: TREE PLANTING

   Perhaps the best BMP is a tree as they intercept rainfall, increase evapotranspiration and increase time of concentration. A portion of the required capture volume can be reduced provided the criteria are met.

CREDITS

 

Deciduous Trees	Evergreen Trees
6 ft3 per tree planted	10 ft3 per tree planted

 

Criteria

To receive credit for planting trees, the following must be met:

   (A)   Trees must be native species (see below), minimum 1” caliper tree and 3 feet tall shrub (min).

   (B)   Trees shall be adequately protected during construction.

   (C)   Trees shall be maintained until redevelopment occurs.

   (D)   No more than 25% of the required capture volume can be mitigated through the use of trees.

   (E)   Dead trees shall be replaced within 12 months.

   (F)   Non-native species are not applicable.

      Req’d Capture Volume (ft3)

   -   Tree Planting Credit (ft3)

      Capture Volume to be managed (ft3)

Sizing of BMP

      How much of the Volume will you manage with a Rain Garden?

   +   How much of the Volume will you manage with a Sump or Trench?

      Capture Volume to be managed (ft3)

Enter the volumes into the Small Project SWM Plan Worksheet on the next sheet.

Native Species Trees (Common Name)

   (A)   Aspen, big-tooth or quaking

   (B)   Basswood, American

   (C)   Blackgum

   (D)   Cherry, black

   (E)   Chokeberry (red or black)

   (F)   Cotton-wood, eastern

   (G)   Cucumber magnolia

   (H)   Dogwood (silky or red osier)

   (I)   Elderberry

   (J)   Hickory, sweet pignut or shag-bark

   (K)   Hophornbeam

   (L)   Ironwood

   (M)   Maple (sugar, red or silver)

   (N)   Mountain laurel

   (O)   Oak (white, swamp white, scarlet, pin, red, black)

   (P)   Pine (pitch or eastern white)

   (Q)   Serviceberry (downy orshadbush)

   (R)   Sycamore, American

   (S)   Tuliptree

   (T)   Willow, black

   (U)   Witch hazel

Credit 2: TREE PLANTING

Perhaps the best BMP is a tree as they intercept rainfall, increase, evapotranspiration and increase time of concentration. A portion of the required capture volume can be reduced provided the criteria are met.

CREDITS

 

Deciduous Trees	Evergreen Trees
(MISSING MATERIAL)	10 ft3 per tree planted

 

SMALL PROJECT SWM PLAN WORKSHEET

   Based upon the information you have provided a Stormwater Plan is required for this development activity. The Stormwater Management Ordinance developed through the Erie County Stormwater Management Act, 32 P.S. §§ 680.1 et seq., regulates compliance requirements for Stormwater Management in this jurisdiction. A complete copy of the Plan can be found on the Erie County Planning Department website (http://www.eriecountyplanning.org) which contains the Model Ordinance.

   Regulated activities shall be conducted only after (municipality) approves a stormwater management plan. The Erie County Stormwater Management Act, 32 P.S. §§ 680.1 et seq., will assist you in preparing the necessary information and plans for (municipality) to review and approve. This document will constitute an approved plan if all of the relevant details are to be installed in their entirety AND no part of the stormwater system adversely affects any other property, nor adversely affect any septic systems or drinking water wells on this, or any other, parcel. Alternative system proposed require a plan will need to be submitted to [municipality] for approval. A design by a qualified professional may be required for more complex sites.

PLEASE INITIAL BELOW TO INDICATE THE STORMWATER MANAGEMENT PLAN FOR THIS SITE

           Minimum Control #1: Erosion and Sediment Pollution Control

           Minimum Control #2: Source Control of Pollution

           Minimum Control #3: Preservation of Natural Drainage Systems and Outfalls

   The relevant details from County Stormwater Management Act, 32 P.S. §§ 680.1 et seq., will be installed in their entirety AND the system will be located as not to adversely affect other property, nor any septic systems or drinking water wells on this, or any other, parcel.

           To meet this requirement, the following will be installed and maintained:

 

Capture Volume to be managed (ft3)			Conversion	Surface Area of BMPs (ft2)
	By Rain Garden 6” ponding; 2’ soil depth	X	1.20
	Dry Well or Infiltration Trench 2 1/2 aggregate depth	X	1.25
	Total		Total

 

           In lieu of meeting the above, an alternative and/or professional design is attached for approval AND the system will be located as not to adversely affect other property, any septic systems or drinking water wells on this, or any other, parcel.

        Site Sketch Plan showing:

•   Property lines with dimensions

•   Proposed septic system, if applicable

•   Proposed buildings with dimensions

•   Proposed well site, if applicable

•   Proposed impervious surfaces with dimensions

•   Proposed stormwater management system(s)

           Operation and Maintenance Agreement

   Condition on approval. The stormwater management plan must, be fully implemented prior to a request for final inspection of the building or zoning permit.

   Acknowledgement. By executing below, the Owner acknowledges the following:

I declare that I am the owner of the property.

•   The information provided is accurate.

•    I further acknowledge that municipal representatives are granted access to the above described property for review and inspection as may be required.

                                                                       Owner            Date:                              

(Ord. 1508, passed 12-20-2010)

APPENDIX F: RELEASE RATE MAP

(Ord. 1508, passed 12-20-2010)