Meadowlark Solar - Copy of Meadowlark_LID Calcs_4-11-18

Surface Type Runoff Infiltration Evapotranspiration
Undisturbed Woods 5% 45%50%
Undisturbed Meadow 7% 45%48%
Disturbed Trees 10% 40%50%
Disturbed Lawn 15% 40%45%
Lawn-Ameded Soil 7% 45%48%
Open Water / BMP 100% 0%0%
Impermeable Surface 85% 5%10%
Land Use
ft2 Surface Type Runoff Infiltration Evapotranspiration
Pasture 1,351,230 98.2%Undisturbed Woods 4.9% 44.2% 49.1%
Woods 25,265 1.8%Undisturbed Woods 0.2% 0.7% 0.9%
Total 1,376,495 100.0%5.1%44.9%50.0%
Land Use
ft2 Surface Type Runoff Infiltration Evapotranspiration
Woods 0 0.0%Undisturbed Woods 0.0% 0.0% 0.0%
Open/Landscaped 1,295,475 94.1%Disturbed Lawns 14.1% 37.6% 42.4%
Concrete Pads, Posts, and Gravel 81,020 5.9%Impermeable Surface 5.0% 0.3% 0.6%
Total 1,376,495 100.0%19.1%37.9%42.9%
General1
Triassic
Basin /
Mountains
Sandhills / Barrier
Islands
Greenfield-Residential2 5% 10%3%
Greenfield-Commercial3 15% 20%15%
Grayfield-Residential2 10% 15%10%
Grayfield-Commercial3 20% 25%20%
1 Includes Piedmont
2 40% impervious or less
3 90% impervious or more
Coverage Hydrologic Fate Determination
Table 2-6. Allowable Tolerance of Hydrologic Fates (From Low Impact
Development: A Guidebook for North Carolina-2009, Chapter 2: Achieving
LID Performance Goals Using a Hydrologic Cycle Approach)
The above referenced tables and calculations have been provided to comply with the low density requirements ( < 6 percent built-upon area) and
also by meeting the post development hydrologic criteria set out in Chapter 2 of the North Carolina Low Impact Development Guidebook dated June
2009. This document (Table 2-2 Hydrologic fate of rainfall at Coweeta, NC, Water 02) allows for a target hydrology for the site of 5 percent runoff, 45
percent for infiltration, and 50 percent evapotranspiration. Table 2-6, Allowable tolerance of hydrologic fates in Chapter 2: Achieving LID
Performance Goals Using a Hydrologic Cycle Approach of the Low Impact Development: A Guidebook for North Carolina-2009 allows for a 15%
tolerance for a Greenfield-Commercial development in the Coastal Region, which would allow up to 20 percent runoff. As shown in the Post-
Development Table, the hydrologic fate falls within the allowable tolerance for a Greenfield-Commercial project within the Coastal Region.
LOW IMPACT DEVELOPMENT CALCULATIONS (MEADOWLARK SOLAR)
Table 2-4. Annual surface runoff, infiltration, and evapotranspiration
percentages for different land surface types (From Low Impact
Development: A Guidebook for North Carolina-2009, Chapter 2: Achieving
LID Performance Goals Using a Hydrologic Cycle Approach)
Pre-Development
Coverage Hydrologic Fate Determination
Post-Development