EX Pool 8 Full Matarrazo Drainage System Approved by Town 3623

Hydrograph Summary Report Page 1 I yd. | Hydrograph| Peak | Time | Timeto | Volume | Return | Inflow Maximum | Maximum Hydrograph oO. type flow | interval| peak period hyd(s) elevation storage description (origin) (cfs) (min) (min) (cuft) (yrs) (ft) (cuft) 1 SCS Runoff | 0.4 6 732 1,582 2 ree eed PREDEVELOPED INFLO. 2 SCS Runoff | 1.2 2 724 4,175 2 — wate coca DEVELOPED INFLOW 2 3 Reservoir 0.3 2 744 3,286 2 2 610.14 2,025 2 Year Routing 5 SCS Runoff | 0.9 6 732 3,668 10 ee eel PREDEVELOPED INFLO 6 SCS Runoff | 2.0 2 724 6,892 10 —_ Cael [lined DEVELOPED INFLOW 1 7 Reservoir 0.6 2 740 6,003 10 6 611.69 2,832 10 Year Routing 9 SCS Runoff | 1.7 6 732 7,233 100 — — — PREDEVELOPED INFLO 10 SCS Runoff | 3.1 2 724 10,972 100 _ oe om DEVELOPED INFLOW 1 4 Reservoir 1.4 2 732 10,083 100 10 613.34 3,684, 100 Year Routing roj. file: COHN.GPW IDF file: Sample.IDF Run date: 12-16-2022 RESPONSE TO OPRA 2024-53_ 000009

Reservoir Report Page 4 Reservoir No. 1 - DRYWELLS Pond Data Pond storage is based on known contour areas Stage / Storage Table English Stage Elevation Contour area Incr.Storage Total storage ft ft sqft cuft cuft 0.00 606.75 350 (0) 0) 0.90 607.65 350 350 350 1.00 607.75 519 435 785 2.00 608.75 519 519 1,304 3.00 609.75 519 519 1,823 4.00 610.75 519 519 2,342 5.00 611.75 519 519 2,861 6.00 612.75 519 519 3,380 7.00 613.75 519 519 3,899 7.10 613.85 350 435 4,334 8.00 614.75 350 350 4,684 Culvert / Orifice Structures Weir Structures IA) = [BJ]. s[c¢]_— [D) (Al {B] [¢] [0] Rise in 3.0 40 0.0 0.0 CrestLenft = 4.0 0.0 0.0 0.0 Span in 3.0 4.0 0.0 0.0 Crest El. ft = 613.25 0.00 0.00 0.00 No. Barrels 4 1 0 0 Weir Coeff. = 3.00 0.00 0.00 0.00 Invert El. ft 608.00 611.25 0.00 0.00 Eqn. Exp. = 1.50 0.00 0.00 0.00 Length ft 1.0 1.0 0.0 0.0 Multi-Stage = No No No No Slope % 1.00 1.00 0.00 0.00 N-Value 013 .013 .000 = .000 Orif. Coeff. 0.60 0.60 0.00 0.00 Multi-Stage = No No No Tailwater Elevation = 0.00 ft Note: All oufiows have been analyzed under inlet and outlet contr Stage / Storage / Discharge Table Stage Storage Elevation ClvA ClvB ClvC ClyvD WrA WrB WrC WrD_ Discharge ft cuft ft cfs cfs cfs cfs cfs cfs cfs cfs cfs 0.00 0 606.75 0.00 0.00 -—- _ 0.00 -- = — 0.00 0.90 350 607.65 0.00 0.00 —- = 0.00 -— a — 0.00 1.00 785 607.75 0.00 0.00 -~- = 0.00, --- = = 0.00 2.00 1,304 608.75 0.19 0.00 -- —_ 0.00 -—~ _ _ 0.19 3.00 1,823 609.75 0.30 0.00 -- — 0.00 -- - _ 0.30 4.00 2,342 610.75 0.38 0.00 -- = 0.00 _ —_ 0.38 5.00 2,861 611.75 0.45 0230 — _ 0.00 — _ = 0.68 6.00 3,380 612.75 0.51 049° -—- = 0.00 — = =e 0.99 7.00 3,899 613.75 0.56 064 -- = 424 — = = 5.44 7.10 4,334 613.85 0.57 066 ~~ — 5,58 — _ _ 6.80 8.00 4,684 614.75 0.61 Q77 0 oa 22.05 — ~ _ 23.42 RESPONSE TO OPRA 2024-53_ 000010

Stage (ft) DRYWELLS 5 10 15 20 Discharge (cfs) 25 7 Total 4 CulvA # CulvB 7 CulvC 7 CulvD Weir A 7 Weir B 7 Weir C 7 Weir D RESPONSE TO OPRA 2024-53_000011

Stage (ft) DRYWELLS 7 | a“ ZO a ZO 0 0 a 1000 2000 3000 4000 5000 Storage (cuft) RESPONSE TO OPRA 2024-53_ 000012

Hydrograph Report Page 1 English Hyd. No. 1 PREDEVELOPED INFLOW 2 Hydrograph type = SCS Runoff Peak discharge = 0.36 cfs Storm frequency = 2 yrs Time interval = 6 min Drainage area = 0.40 ac Curve number = 75 Basin Slope = 1.0% Hydraulic length = 100 ft Te method = USER Time of conc. (Te) = 15 min Total precip. = 3.30 in Distribution = Type Ill Storm duration = 24 hrs Shape factor = 484 Total Volume = 1,582 cuft Hydrograph Discharge Table Time -- Outflow Time -- Outflow Time -- Outflow Time -- Outflow (hrs cfs) (hrs cfs) (hrs cfs) (hrs cfs) 10.90 0.00 14.10 0,04 17.30 0.02 20.50 0.01 11.00 0.04 14.20 0.04 17.40 0.02 20.60 0.01 11.10 0.04 14.30 0.04 17.50 0.02 20.70 0.01 11.20 0.01 14.40 0.04 17.60 0.02 20.80 0.01 11.30 0.01 14.50 0.03 17.70 0.02 20.90 0.01 11.40 0.01 14.60 0.03 17.80 0.01 21.00 0.04 11.50 0.02 14.70 0.03 17.90 0.04 21.10 0.01 11.60 0.02 14.80 0.03 18.00 0.01 21.20 0.01 11.70 0.04 14.90 0.03 18.10 0.01 21.30 0.01 11.80 0.06 15.00 0.03 18.20 0.01 21.40 0.01 11.90 0.10 15.10 0.03 18.30 0.01 21.50 0.01 12.00 0.18 16.20 0.03 18.40 0.01 21.60 0.01 12.10 0.30 15.30 0.03 18.50 0.01 21.70 0.01 12.20 0.36 << 15.40 0.03 18.60 0.01 21.80 0.01 12.30 0.32 15.50 0.03 18.70 0.01 21.90 0.04 12.40 0.25 15.60 0.03 18.80 0.01 22.00 0.01 12.50 0.18 15.70 0.03 18.90 0.01 22.10 0.01 12.60 0.13 15.80 0.02 19.00 0.01 22.20 0.01 12.70 0.10 15.90 0.02 19.10 0.04 22.30 0.01 12.80 0.08 16.00 0.02 19.20 0.01 22.40 0.04 12.90 0.07 16.10 0.02 19.30 0.01 22.50 0.01 13.00 0.06 16.20 0.02 19.40 0.01 22.60 0.01 13.10 0.06 16.30 0.02 19.50 0.01 22.70 0.04 13.20 0.05 16.40 0.02 19.60 0.01 22.80 0.01 13.30 0.05 16.50 0.02 19.70 0.01 22.90 0.01 13.40 0.05 16.60 0.02 19.80 0.04 23.00 0.01 13.50 0.05 16.70 0.02 19.90 0.01 23.10 0.01 13.60 0.05 16.80 0.02 20.00 0.01 23.20 0.01 13.70 0.05 16.90 0.02 20.10 0.01 23.30 0.01 13.80 0.04 17.00 0.02 20.20 0.01 23.40 0.01 13.90 0.04 17.10 0,02 20.30 0.01 23.50 0.01 14.00 0.04 17.20 0.02 20.40 0.01 23.60 0.01 Continues on next page... RESPONSE TO OPRA 2024-53_ 000013

PREDEVELOPED INFLOW 2 Page 2 Hydrograph Discharge Table Time -- Outflow (hrs cfs) 23.70 0.01 23.80 0.01 23.90 0.01 24.00 0.01 24.10 0.01 ..End RESPONSE TO OPRA 2024-53_ 000014

Q cfs 1 - SCS Runoff - 2 Yr - Qp = 0.36 cfs 0.4 0.3 0.2 0.1 0.0 7 Hyd. 1 _ | a 0 5 10 45 2025 Time (hrs) RESPONSE TO OPRA 2024-53_ 000015

Hydrograph Report Page 1 English Hyd. No. 2 DEVELOPED INFLOW 2 Hydrograph type = SCS Runoff Peak discharge = 1.24 cfs Storm frequency = 2 yrs Time interval = 2 min Drainage area = 0.40 ac Curve number = 98 Basin Slope = 1.0% Hydraulic length = 100 ft Te method = USER Time of conc. (Tc) = 5 min Total precip. = 3.30 in Distribution = Type Ill Storm duration = 24 hrs Shape factor = 484 Total Volume = 4,175 cuft Hydrograph Discharge Table Time -- Outflow Time -- Outflow Time -- Outflow Time -- Outflow (hrs cfs) (hrs cfs) (hrs cfs) (hrs cfs) 5.23 0.01 6.30 0.02 7.37 0.02 8.43 0.03 5.27 0.01 6.33 0.02 7.40 0.02 8.47 0.03 5.30 0.01 6.37 0.02 7.43 0.02 8.50 0.03 5.33 0.01 6.40 0.02 TAT 0.02 8.53 0.03 5,37 0.01 6.43 0.02 7.50 0.02 8.57 0.03 5.40 0.01 6.47 0.02 7.53 0.02 8.60 0.04 5.43 0.01 6.50 0.02 7.57 0.02 8.63 0.04 5.47 0.01 6.53 0.02 7.60 0,02 8.67 0.04 5.50 0.01 6.57 0.02 7.63 0.02 8.70 0.04 5.53 0.01 6.60 0.02 7.67 0.03 8.73 0.04 5.57 0.01 6.63 0.02 7.70 0.03 8.77 0.04 5.60 0.01 6.67 0.02 7.73 0.03 8.80 0.04 5.63 0.01 6.70 0.02 7.77 0.03 8.83 0.04 5.67 0.01 6.73 0.02 7.80 0.03 8.87 0.04 5.70 0.01 6.77 0.02 7.83 0.03 8.90 0.04 5.73 0.01 6.80 0.02 7.87 0.03 8.93 0.04 5.77 0.01 6.83 0.02 7.90 0.03 8.97 0.04 5.80 0.01 6.87 0.02 7.93 0.03 9.00 0.04 5.83 0.01 6.90 0.02 7.97 0.03 9.03 0.04 5.87 0.01 6.93 0.02 8.00 0.03 9.07 0.04 5.90 0.01 6.97 0.02 8.03 0.03 9.10 0.04 5.93 0.01 7.00 0.02 8.07 0.03 9.13 0.04 5.97 0.01 7.03 0.02 8.10 0.03 9.17 0.04 6.00 0.01 7.07 0.02 8.13 0.03 9.20 0.04 6.03 0.01 7.10 0.02 8.17 0.03 9.23 0.04 6.07 0.01 7.13 0.02 8.20 0.03 9.27 0.05 6.10 0.02 TAT 0.02 8.23 0.03 9.30 0.05 6.13 0.02 7.20 0.02 8.27 0.03 9.33 0.05 6.17 0.02 7.23 0.02 8.30 0.03 9.37 0.05 6.20 0.02 7.27 0.02 8.33 0.03 9.40 0.05 6.23 0.02 7.30 0.02 8.37 0.03 9.43 0.05 6.27 0.02 7.33 0.02 8.40 0.03 9.47 0.05 Continues on next page... RESPONSE TO OPRA 2024-53_ 000016

DEVELOPED INFLOW 2 Page 2 Hydrograph Discharge Table Time -- Outflow Time -- Outflow Time -- Outflow Time -- Outflow (hrs cfs) (hrs cfs) (hrs cfs) (hrs cfs) 9.50 0.05 11.13 0.10 12.77 0.12 14.40 0.06 9.53 0.05 11.17 0.10 12.80 0.12 14.43 0.06 9.57 0.05 11.20 0.10 12.83 0.12 14.47 0.06 9.60 0.05 11.23 0.11 12.87 0.11 14.50 0.05 9.63 0.05 11.27 0.11 12.90 0.11 14.53 0.05 9.67 0.05 11.30 0.11 12.93 0.11 14.57 0.05 9.70 0.05 11.33 0.12 12.97 0.10 14.60 0.05 9.73 0.05 11.37 0.12 13.00 0.10 14.63 0.05 9.77 0.05 11.40 0.13 13.03 0.09 14.67 0.05 9.80 0.05 11.43 0.13 13.07 0.09 14.70 0.05 9.83 0.05 11.47 0.13 13.10 0.09 14.73 0.05 9.87 0.05 11.50 0.14 13.13 0.09 14.77 0.05 9.90 0.05 11.53 0.14 13.17 0.09 14.80 0.05 9.93 0.06 11.57 0.16 13.20 0.09 14.83 0.05 9.97 0.06 11.60 0.19 13.23 0.09 14.87 0.05 10.00 0.06 11.63 0.22 13.27 0.08 14.90 0.05 10.03 0.06 11.67 0.26 13.30 0.08 14.93 0.05 10.07 0.06 11.70 0.29 13.33 0.08 14.97 0.05 10.10 0.06 11.73 0.33 13.37 0.08 15.00 0.05 10.13 0.06 11.77 0.36 13.40 0.08 15.03 0.05 10.17 0.06 11.80 0.40 13.43 0.08 15.07 0.05 10.20 0.06 11.83 0.44 13.47 0.08 15.10 0.05 10.23 0.06 11.87 0.47 13.50 0.08 15.13 0.05 10.27 0.06 11.90 0.51 13.53 0.08 15.17 0.05 10.30 0.06 11.93 0.57 13.57 0.08 15.20 0.04 10.33 0.07 11.97 0.72 13.60 0.07 16.23 0.04 10.37 0.07 12.00 0.95 13.63 0.07 15.27 0.04 10.40 0.07 12.03 1.17 13.67 0.07 15.30 0.04 10.43 0.07 12.07 1.24 << 13.70 0.07 15.33 0.04 10.47 0.07 12.10 1.10 13.73 0.07 15.37 0.04 10.50 0.07 12.13 0.86 13.77 0.07 15.40 0.04 10.53 0.07 12.17 0.66 13.80 0.07 15.43 0.04 10.57 0.07 12.20 0.56 13.83 0.07 15.47 0.04 10.60 0.07 12.23 0.50 13.87 0.07 15.50 0.04 10.63 0.07 12.27 0.47 13.90 0.07 15.53 0.04 10.67 0.08 12.30 0.43 13.93 0.06 15.57 0.04 10.70 0.08 12.33 0.40 13.97 0.06 15.60 0.04 10.73 0.08 12.37 0.36 14.00 0.06 15.63 0.04 10.77 0.08 12.40 0.32 14.03 0.06 15.67 0.04 10.80 0.08 12.43 0.29 14.07 0.06 15.70 0.04 10.83 0.08 12.47 0.25 14.10 0.06 15.73 0.04 10.87 0.08 12.50 0.21 14.13 0.06 15.77 0.04 10.90 0.08 12.53 0.18 14.17 0.06 15.80 0.04 10.93 0.08 12.57 0.16 14.20 0.06 15.83 0.04 10.97 0.08 12.60 0.15 14.23 0.06 15.87 0.04 11.00 0.09 12.63 0.14 14.27 0.06 15.90 0.03 11.03 0.09 12.67 0.14 14.30 0.06 15.93 0.03 11.07 0.09 12.70 0.13 14.33 0.06 15.97 0.03 11.10 0.09 12.73 0.13 14.37 0.06 16.00 0.03 Continues on next page. RESPONSE TO OPRA 2024-53_000017

DEVELOPED INFLOW 2 Page 3 Hydrograph Discharge Table Time -- Outflow Time -- Outflow Time -- Outflow Time -- Outflow (hrs cfs) (hrs cfs) (hrs cfs) (hrs cfs) 16.03 0.03 17.67 0.02 19.30 0.02 20.93 0.01 16.07 0.03 17.70 0.02 19.33 0.02 20.97 0.01 16.10 0.03 17.73 0.02 19.37 0.02 21.00 0.01 16.13 0.03 17.77 0.02 19.40 0.02 21.03 0.01 16.17 0.03 17.80 0.02 19.43 0.02 21.07 0.01 16.20 0.03 17.83 0.02 19.47 0.02 21.10 0.01 16.23 0.03 17.87 0.02 19.50 0.02 21.13 0.01 16.27 0.03 17.90 0.02 19.53 0.02 21.17 0.01 16.30 0.03 17.93 0.02 19.57 0.02 21.20 0.01 16.33 0.03 17.97 0.02 19.60 0.02 21.23 0.01 16.37 0.03 18.00 0.02 19.63 0.02 21.27 0.01 16.40 0.03 18.03 0.02 19.67 0.02 21.30 0.01 16.43 0.03 18.07 0.02 19.70 0.02 21.33 0.01 16.47 0.03 18.10 0.02 19.73 0.02 21.37 0.01 16.50 0.03 18.13 0.02 19.77 0.02 21.40 0.01 16.53 0.03 18.17 0.02 19.80 0.02 21.43 0.01 16.57 0.03 18.20 0.02 19.83 0.02 21.47 0.01 16.60 0.03 18.23 0,02 19.87 0.02 21.60 0.01 16.63 0.03 18.27 0.02 19.90 0.02 21.53 0.01 16.67 0.03 18.30 0.02 19.93 0.02 21.57 0.01 16.70 0.03 18.33 0.02 19.97 0.02 21.60 0.01 16.73 0.03 18.37 0.02 20.00 0.02 21.63 0.01 16.77 0.03 18.40 0.02 20.03 0.02 21.67 0.01 16.80 0.03 18.43 0.02 20.07 0.02 21.70 0.01 16.83 0.03 18.47 0.02 20.10 0.02 21.73 0.01 16.87 0.03 18.50 0.02 20.13 0.02 21.77 0.01 16.90 0.03 18.53 0.02 20.17 0.02 21.80 0.01 16.93. 0.03 18.57 0.02 20.20 0.02 21.83 0.01 16.97 0.03 18.60 0.02 20.23 0.02 21.87 0.01 17.00 0.03 18.63 0.02 20.27 0.02 21.90 0.01 17.03 0.03 18.67 0.02 20.30 0.02 21.93 0.01 17.07 0.03 18.70 0.02 20.33 0.02 21.97 0.01 17.10 0.03 18.73 0.02 20.37 0.02 22.00 0.01 17.13 0.03 18.77 0.02 20.40 0.02 22.03 0.02 1717 0.03 18.80 0,02 20.43 0.02 22.07 0.02 17.20 0.03 18.83 0.02 20.47 0.02 22.10 0.02 17.23 0.03 18.87 0.02 20.50 0.02 22.13 0.02 17.27 0.02 18.90 0.02 20.53 0.02 22.17 0.01 17.30 0.02 18.93 0.02 20.57 0.02 22.20 0.01 17.33 0.02 18.97 0.02 20.60 0.02 22.23 0.01 17.37 0.02 19.00 0.02 20.63 0.02 22.27 0.01 17.40 0.02 19.03 0.02 20.67 0.02 22.30 0.01 17.43 0.02 19.07 0.02 20.70 0.01 22.33 0.01 17.47 0.02 19.10 0.02 20.73 0.01 22.37 0.01 17.50 0.02 19.13 0.02 20.77 0.01 22.40 0.01 17.53 0.02 19.17 0.02 20.80 0.01 22.43 0.01 17.57 0.02 19.20 0.02 20.83 0.01 22.47 0.01 17.60 0.02 19.23 0.02 20.87 = 0.01 22.50 0.01 17.63 0.02 19.27 0.02 20.90 0.01 22.53 0.01 Continues on next page... RESPONSE TO OPRA 2024-53_ 000018