NC Central University P3 - Chidley South - Chidley South SNAP Report

Project Information
Project Name:NCCU P3 - Chidley South
Submission Date:03/12/2019
Project Area (ft2):149,894 ft2
Disturbed Area (ft2):149,894 ft2
Development Land Use Type:Institutional
Development Activity Type:Development - Expansion
Designated Downtown Area?no
Project Location/Address:1400 S. Alston Ave, Durham
County:Durham
Local Jurisdiction:Durham
Project Latitude Coordinates:35.973494 N
Project Longitude Coordinates:78.894286 W
Precipitation Station:Durham
Physiographic Region:Triassic Basin
Nutrient Management Watershed:Jordan Lake
Subwatershed:Jordan - Upper New Hope
Phosphorus Delivery Zone:Jordan - 030030
Nitrogen Delivery Zone:Jordan - 030030
Project Designer and Contact Phone
Number / Email:Patrick Covil - 919-424-3763; [e-mail]
Part of Common Development Plan?yes
Project Owner Type:State non-NCDOT
Project Description:Demolition of an existing dorm and construction of a new dorm.
Project Area Land Cover Characteristics
Roof 1.18 0.11 14,518 28,234
Roadway 1.64 0.34
Parking/Driveway/Sidewalk 1.42 0.18 15,479 52,940
Protected Forest 0.97 0.03
Other Pervious/Landscaping 2.48 1.07 119,897 68,720
CUSTOM LAND COVER 1
CUSTOM LAND COVER 2
CUSTOM LAND COVER 3
LAND TAKEN UP BY SCM 1.18 0.11
SIMPLE METHOD Stormwater Runoff Volume Generated, V
Runoff Coefficient, R v V =Pj * Rv * (P/12) * A
Rv = 0.05 + (0.009 *I) where A =
drainage area (ft2)
where I = percent impervious (%)
Pj =
Average Annual Pollutant Load, L P =
L =
where C =
Pre-Project:Post-Project:
A = 3.4411 ac A =3.4411 ac
P = 47.81 in.P =47.81 in.
V = 123680 ft3 V =288837 ft3
I = 20%I = 54%
Rv = 0.23 Rv = 0.54
Pj = 0.9 Pj = 0.9
CTN = 1.51 mg/L CTN = 1.39 mg/L
CTP = 0.31 mg/L CTP = 0.19 mg/L
LTN = 11.65 lb/yr LTN = 24.98 lb/yr
LTP = 2.37 lb/yr LTP = 3.51 lb/yr
Net Change of Land Covers (ft2):51,177
Total Pre-Project Calculated Area (ft 2):
Total Post-Project Calculated Area (ft2):
Total Project Area Entered (ft2):149,894
149,894
149,894
LAND COVER AREA CHECK
PROJECT AREA LAND COVERS
TN
EMC
(mg/L)
TP
EMC
(mg/L)
Post-
Project
Area (ft2)
Pre-
Project
Area (ft2)
event mean concentration (mg/L)
Equations Used and Project Area Calculations
fraction of rain events with runoff
average annual rainfall depth (in)
(Pj * Rv * (P/12 )) * (C * A * 2.72)
3. SCM Characteristics
Catchment ID 1 1 1
SCM ID 101 102 103
Type of SCM Sand Filter per MDC -
Closed
Predominant hydrologic soil
group at SCM location D
SCM Description
Design Storm Size (inches/24hrs) 1.00
Percent of Full Size 100%
Hydrologic Value - Percent
Annual Effluent 90%
Hydrologic Value - Percent
Annual Overflow 10%
Hydrologic Value - Percent
Annual ET/Infiltrated 0%
SCM Effluent TP EMC (mg/L)0.12
SCM Effluent TN EMC (mg/L)1.20
SCM Land Cover TP EMC (mg/L)0.11
SCM Land Cover TN EMC (mg/L)1.18
Drains to SCM ID 0
SCM Characteristics
3. SCM Characteristics
Catchment Routing
(Source Catchment)Catchments Draining to
SCM 101
Catchments Draining to
SCM 102
Catchments Draining to
SCM 103
Catchment 1
Catchment 2
Catchment 3
Catchment 4
Catchment 5
Catchment 6
SCM ID:101 102 103
SCM Drainage Area Land Covers Area Draining Directly to
SCM 101 (ft2)
Area Draining Directly to
SCM 102 (ft2)
Area Draining Directly to
SCM 103 (ft2)
Roof 14,654
Roadway
Parking/Driveway/Sidewalk 19,985
Protected Forest
Other Pervious/Landscaping 5,872
CUSTOM LAND COVER 1
CUSTOM LAND COVER 2
CUSTOM LAND COVER 3
LAND TAKEN UP BY SCM
TOTAL AREA DRAINING TO SCM
(ft2):40,511 0 0
CATCHMENT AREA (ft2):40,511
3. SCM Characteristics
Catchment ID
SCM ID
Type of SCM
Predominant hydrologic soil
group at SCM location
SCM Description
Design Storm Size (inches/24hrs)
Percent of Full Size
Hydrologic Value - Percent
Annual Effluent
Hydrologic Value - Percent
Annual Overflow
Hydrologic Value - Percent
Annual ET/Infiltrated
SCM Effluent TP EMC (mg/L)
SCM Effluent TN EMC (mg/L)
SCM Land Cover TP EMC (mg/L)
SCM Land Cover TN EMC (mg/L)
Drains to SCM ID
SCM Characteristics
3. SCM Characteristics
Catchment Routing
(Source Catchment)
Catchment 1
Catchment 2
Catchment 3
Catchment 4
Catchment 5
Catchment 6
SCM ID:
SCM Drainage Area Land Covers
Roof
Roadway
Parking/Driveway/Sidewalk
Protected Forest
Other Pervious/Landscaping
CUSTOM LAND COVER 1
CUSTOM LAND COVER 2
CUSTOM LAND COVER 3
LAND TAKEN UP BY SCM
TOTAL AREA DRAINING TO SCM
(ft2):
CATCHMENT AREA (ft2):
Total Land Use Area
Treated By All SCMs (ft2)
Allowable Total Land Use
Area to be Treated Based
on Post-Project Areas (ft2)
Post-Project Untreated
Land Area (ft2)
14,654 28,234 13,580
0 0 0
19,985 52,940 32,955
0 0 0
5,872 68,720 62,848
0 0 0
0 0 0
0 0 0
0 0 0
40,511 149,894 109,383
Project Summary149,894ft23.4411acres149,894ft23.4411acres8%25%0.822.202.827.573.2524.100.948.000.6917.410.4316.530.034.13 Nutrient Export SummaryPre-Project Whole Site ConditionsPost-Project Whole Site without SCMsPost-Project Whole Site with SCMsPost-Project SCM-Treated AreaPost-Project Untreated Area20.0% 54.2% 54.2% 85.5% 42.5%20.0% 54.2% 54.2% 85.5% 42.5%123,680 288,837 288,837 119,049 169,7880% 134% 134%1.51 1.39 1.34 1.21 1.4211.65 24.98 24.109.00 15.103.39 7.26 7.00 9.68 6.010% 114% 107%0.31 0.19 0.18 0.12 0.222.37 3.51 3.250.92 2.330.69 1.02 0.94 0.99 0.930% 48% 37%DurhamLocal Jurisdiction:DurhamTotal Phosphorus % Change (relative to pre-D)Total P Load Reduction Needed (lb/yr):Nitrogen Loading Rate Target (lb/ac/yr):Nitrogen Load Target at Site (lb/yr):Nitrogen Load Leaving Site w/SCMs (lb/yr):N Offsite Buy-Down Threshold Loading Rate Total N Load Reduction Needed (lb/yr):State non-NCDOTSubmission Date:March 12, 2019Total Phosphorus Load Leaving Site (lb/yr)Total Phosphorus Loading Rate (lb/ac/yr)Percent Built-Upon Area (BUA) (%)Annual Runoff Volume (ft3/yr)Annual Runoff % Change (relative to pre-D)Total Nitrogen EMC (mg/L)Total Nitrogen Load Leaving Site (lb/yr)Development Activity Type:Percent Impervious (for runoff calculation) (%)Total Phosphorus EMC (mg/L)Phosphorus Loading Rate Target (lb/ac/yr):Phosphorus Load Target at Site (lb/yr):Phosphorus Load Leaving Site w/SCMs (lb/yr):P Offsite Buy-Down Threshold Loading Rate (lb/ac/yr):NCCU P3 - Chidley SouthTotal Nitrogen Loading Rate (lb/ac/yr)Total Nitrogen % Change (relative to pre-D)Project Name: Project Area (ft2):Disturbed Area (ft2):County:Development Land Use Type:P Load Treatment Balance at Lake (lb/yr): N Load Treatment Balance at Lake (lb/yr):Nutrient Management Watershed:Phosphorus Delivery Zone:N Load Treatment Balance at Site (lb/yr):Phosphorus Delivery Factor (%):P Load Treatment Balance at Site (lb/yr):Nitrogen Delivery Factor (%):Owner Type:Designated Downtown Area?Subwatershed:Nitrogen Delivery Zone:InstitutionalnoJordan - Upper New HopeJordan - 030030Jordan LakeJordan - 030030Development - Expansion
SCM/Catchment SummaryVolume Reduction (%)TN Out (mg/L) TP Out (mg/L)TN Out (lbs/ac/yr)TP Out (lbs/ac/yr)TN Reduction (%)TP Reduction (%)0.00% 1.21 0.129.68 0.998.87% 21.92%0.00% 1.21 0.129.68 0.998.87% 21.92%0.00% 0.00 0.000.00 0.000.00% 0.00%0.00% 0.00 0.000.00 0.000.00% 0.00%0.00% 0.00 0.000.00 0.000.00% 0.00%0.00% 0.00 0.000.00 0.000.00% 0.00%0.00% 0.00 0.000.00 0.000.00% 0.00%0.00% 0.00 0.000.00 0.000.00% 0.00%0.00% 0.00 0.000.00 0.000.00% 0.00%0.00% 0.00 0.000.00 0.000.00% 0.00%0.00% 0.00 0.000.00 0.000.00% 0.00%0.00% 0.00 0.000.00 0.000.00% 0.00%0.00% 0.00 0.000.00 0.000.00% 0.00%0.00% 0.00 0.000.00 0.000.00% 0.00%0.00% 0.00 0.000.00 0.000.00% 0.00%0.00% 0.00 0.000.00 0.000.00% 0.00%0.00% 0.00 0.000.00 0.000.00% 0.00%0.00% 0.00 0.000.00 0.000.00% 0.00%0.00% 0.00 0.000.00 0.000.00% 0.00%0.00% 0.00 0.000.00 0.000.00% 0.00%0.00% 0.00 0.000.00 0.000.00% 0.00%0.00% 0.00 0.000.00 0.000.00% 0.00%0.00% 0.00 0.000.00 0.000.00% 0.00%0.00% 0.00 0.000.00 0.000.00% 0.00%602: NA603: NA501: NA502: NACatchment 6503: NA601: NACatchment 3Catchment 4Catchment 5202: NA203: NA301: NA302: NA303: NA401: NA402: NA403: NA102: NA101: Sand Filter per MDC - ClosedSCM ID and Type103: NA201: NACatchment 1Catchment 2SCM rows in red have a data entry error for the SCM that makes an error in the calculation.
Type of SCM:Sand Filter per MDC - ClosedArea Treated by SCM (ft2):40,511Percent Impervious of Contributing Watershed (%): 86%Runoff Coefficient, Rv:0.82Inflow Volume (ft3):119,049Incoming Total Nitrogen Concentration (mg/L): 1.33Annual Incoming Total Nitrogen Load (lbs): 9.88Incoming Total Phosphorus Concentration (mg/L): 0.16Annual Incoming Total Phosphorus Load (lbs): 1.18Total Volume Leaving SCM (ft3):119,049Outgoing Total Nitrogen Concentration (mg/L): 1.21Annual Outgoing Total Nitrogen Load (lbs): 9.00Outgoing Total Phosphorus Concentration (mg/L): 0.12Annual Outgoing Total Phosphorus Load (lbs): 0.92Annual Volume Reduction by SCM (ft3):0Annual Volume Reduction by SCM (%): 0%Annual Total Nitrogen Reduction by SCM (%): 8.87%Annual Total Nitrogen Reduction by SCM (lb): 0.88Annual Total Phosphorus Reduction by SCM (%): 21.92%Annual Total Phosphorus Reduction by SCM (lb): 0.26Rv = 0.05 + (0.009 *I), where I = percent impervious (%)Supporting CalculationsV = Pj * Rv * A * (P/12), where A = area of catchment (ft2) P = average annual rainfall depth (in)CATCHMENT 1, SCM 101L = ((P * Pj * Rv) ÷ (12 )) * (C * A * 2.72) where L = annual pollutant loading (lbs) Pj = fraction of rain events that produce runoff (dec) C = event mean concentration of pollutant (mg/L)Lout = Vout * EMCout * 6.243ᴇ-5 where Vout = outflow volume (ft3), EMCout = effluent median concentration (mg/L)Vout = Vin * (1 - Red) where Vin = inflow volume (ft3) Red = volume reduction by SCM (%)
Durham
8.00
0.94
25%
8%
(A) (B) (C) (D) (E) (F) (G) (H)
(L) (Where
Applicable)
Untreated
Loading Rate
(lbs/ac/yr)
Treated
Loading Rate
(lbs/ac/yr)
Loading Rate
Target
(lbs/ac/yr)
Reduction
Need
(lbs/ac/yr)
Project Size
(ac)
Offset
Duration (yrs)
Delivery
Factor (%)
State Buy
Down Amount
(lbs)
Local Gov’t
Buy Down
Amount (lbs)
B - C D * E * F * G
7.26 7.00 2.20 4.80 3.4411 30 25%124.00
(A) (B) (C) (D) (E) (F) (G) (H)
(L) (Where
Applicable)
Untreated
Load Rate
(lbs/ac/yr)
Treated Load
Rate
(lbs/ac/yr)
Loading Rate
Target
(lbs/ac/yr)
Reduction
Need
(lbs/ac/yr)
Project Size
(ac)
Offset
Duration (yrs)
Delivery
Factor (%)
State Buy
Down Amount
(lbs)
Local Gov’t
Buy Down
Amount (lbs)
B - C D * E * F * G
1.02 0.94 0.82 0.12 3.4411 30 8%1.03
Phone:
Date:
http://deq.nc.gov/about/divisions/water-resources/planning/nonpoint-source-management/nutrient-offset-
information
Nutrient Management Strategy Watershed - Nutrient Offset Credit Reporting Form
Project Address:
Project Name:
Applicant Name:
NCCU P3 - Chidley South
1400 S. Alston Ave, Durham
Please complete and submit the following information to the local government permitting your development project
to characterize it and assess the need to purchase nutrient offset credits. Contact and rule implementation
information can be found online at:
PROJECT INFORMATION
Staff Name:
Development - Expansion
Project Latitude:
Project Longitude:
LOCAL GOVERNMENT AUTHORIZATION
Local Government Name:
N Offsite Threshold Rate (lb/ac/yr):
Pre-Project Built-Upon Area %:
Post-Project Built-Upon Area %:
Nutrient Management Watershed:
Subwatershed:
Nitrogen Delivery Zone:
Phosphorus Delivery Zone:
Development Land Use Type:
Development Activity Type:
Institutional
Nitrogen Delivery Factor:
Phosphorus Delivery Factor:
Jordan Lake
Jordan - Upper New Hope
Jordan - 030030
Jordan - 030030
Local Government Authorizing Signature:
Staff Email:
Date: (mm/dd/yyyy)
County:
Durham
35.973494
78.894286
20.01%
54.15%
WATERSHED INFORMATION
P Offsite Threshold Rate (lb/ac/yr):
NUTRIENT OFFSET REQUEST
Phosphorus Load Offset Needs
Nitrogen Load Offset Needs