Introduction. The System. Model Limitations, Assumptions, and Parameters. Optional Services Tech Memo

Transcription

1 Optional Services Tech Memo Introduction This technical memo evaluates the impact of a tide gate to be installed at the confluence of the Left Bank Tributary of Thalia Creek and Lake Windsor. Specifically, it analyzes the effect of pumping the stormwater flow from the lake into the creek on the Windsor Woods drainage area, Lake Windsor, and the Left Bank Tributary of Thalia Creek. The memo is an addendum to the draft report on Princess Anne Plaza Watershed Study and expands the study to include this additional scenario. Thalia Creek is a tidal creek hydraulically connected to Lake Windsor by a weir like opening that is approximately 83 feet at normal lake levels. Since Thalia Creek is tidal, it makes Lake Windsor and the Windsor Woods Canal a tidal system. The system is adequate to drain normal rainfall events during normal tides, but heavy rainfall coupled with high tides can overwhelm the system resulting in frequent flooding of this area. The draft reports Princess Anne Plaza Watershed Study and Windsor Woods Pump Station Preliminary Engineering Report discuss the impact of a 30 cfs pump station at South Blvd, and a tide gate at the triple culverts under I-26, respectively. This technical memo discusses the impact of a pump station with the tide gate at the confluence of Thalia Creek and Lake Windsor on the stormwater and drainage system. In order to determine the impacts of the stormwater pump station and location of the tide gate on the drainage system in Windsor Woods and Thalia Creek, the Watershed 1D stormwater model EPASWMM 5.0 that was developed for the Princess Anne Plaza Watershed Study was exported into a 1D XPSWMM version The XPSWMM model was validated with field data and pictures for 3 storms: Ernesto, Sandy, and a small storm on July 12, 2013, and culvert data was compared with the culvert program HY-8. This report also determines the optimal pumping rate of a pump station if a tide gate is installed at the Thalia Creek and Lake Windsor confluence, and computes the peak water surface elevations in Thalia Creek, Lake Windsor, Windsor Woods Canal, and Rosemont Road. The System As described in the draft report Princess Anne Plaza Watershed Study, the Windsor Woods drainage system is not adequate to convey the 10-year storm. Because of the intensity and extremely low elevations, the system can not to convey the 10-year storm without flooding or significant land use changes for storage and flood plain development. However, dredging the main stem of the drainage system, the Windsor Woods Canal, and pumping can significantly reduce the duration of flooding during high intensity storms and high tidal events. Model Limitations, Assumptions, and Parameters The XPSWMM model was used to analyze existing and proposed conditions in this technical memo. The EPA SWMM 5.0 model that was developed for Watershed in the original Princess Anne Watershed Study was imported into XPSWMM for its capability to show streets as conveyance channels during flooding. Because the XPSWMM model developed was originally in the EPASWMM 5.0 format, the infiltration method and storm distribution is the same as that in the EPA Model. Other node and conduit parameters such as length, inverts, and manning s coefficient are also the same. In order to visualize and compare the flooding in the watershed, the streets were modeled as stormwater conveyance channels in the XPSWMM model. 1

2 Optional Services Tech Memo Similar to EPA SWMM, one major assumption in the 1D model is that all flows from a catchment enter the outlet node. While XPSWMM does have the ability to enter the inlet capacity, this level of detail was not included in this XPSWMM model. As such, the assumption is that all runoff from a catchment enters the outlet node, and does not bypass to another node. Similar to the EPA SWMM model, the total run-time is 8 hours to allow the constant tail water elevation simulating tidal effects on the system to normalize before the rainfall is introduced into the system. Model Results The XPSWMM model was run for () storms with a tide level of.7 feet to compare the impacts of different pumping rates on the Left Tributary of Thalia Creek, Lake Windsor, the Windsor Woods Canal, the culverts under I-26, and the Windsor Woods neighborhood. Water surface elevations were noted at several points along Thalia Creek and the Windsor Woods Canal. Water surface elevations on the Presidential Blvd and South Rosemont Road were compared along with approximate length of time of flooding. The 10-year storm was also seen with a 6 foot tide. Plan views, profile views, and dynamic long section views for the system, Lake Windsor, and the canals for each storm are depicted in Appendices A1-A. Water surface elevations for each scenario calculated by the XPSWMM program is listed in Appendix B1-B3. Tables 1-2 show a summary of average water surface elevations at each system trunk calculated by the model for the 10- year storm and the 25- year storm with a tidal event of.7 feet. 2

3 Optional Services Tech Memo Table 1. Summary of average water surface elevations at each system trunk calculated by XPSWMM for 10-year storm.7 ft tide Scenario Culverts under I-26 Storm Year: 10 year -.7 ft tide WSE (ft) Left Trib Left Trib Thalia Thalia Creek Creek st North of S Plaza Lake Crossing Trashmore Conduit name Link 78 L_805 Link 137 Lake Windsor Node 730LW Windsor Woods Canal at Presidential Blvd Rosemont Road L_755A Link 279 existing Conditions Tide Gate at I Tide Gate at confluence with 30 cfs maxpump Tide Gate at confluence with 90 cfs maxpump Tide Gate at confluence with 60 cfs maxpump hour(s) flooded Table 2. Summary of average water surface elevations at each system trunk calculated by XPSWMM for 25-year storm.7 ft tide Scenario Culverts under I-26 Storm Year: 25 year -.7 ft tide WSE (ft) Left Trib Left Trib Thalia Thalia Creek Creek st North of S Plaza Lake Crossing Trashmore Conduit name Link 78 L_805 Link 137 Lake Windsor Node 730LW Windsor Woods Canal at Presidential Blvd Rosemont Road L_755A Link 279 hour(s) flooded existing Conditions Tide Gate at I Tide Gate at confluence with 90 cfs maxpump Tide Gate at confluence with 60 cfs maxpump

4 Optional Services Tech Memo Discussion As mentioned previously, the drainage system is not adequate to convey the 10 year storm. The model was run for a 2 year storm with a 1 foot tide, and the system showed flooding in some areas (Figure 1). Figure 1. Plan view of a 2 year storm with 1 foot tide shows flooding in sections of Windsor Woods When the tide gate is installed at the culverts under I-26, it prohibits the tide from flowing into the drainage system during high tidal events. Rainfall runoff discharge into Thalia Creek is routed into Lake Windsor from where it is pumped out. As a result, the water surface elevation (WSE) in the canal and the Left Tributary of Thalia Creek is kept low as rainfall runoff is discharged into the lake. When the tide gate is positioned at the confluence of Thalia Creek and Lake Windsor, the tide is allowed to continue up Thalia Creek as it currently does (existing conditions). However, the WSE will be higher in the creek than existing conditions because of the additional flows pumping from Lake Windsor into the canal. A graph depicting the WSE of the Left Tributary of Thalia Creek with respect to the maximum pumping rate is shown in Figure 2.

5 Water Sruface Elevation Optional Services Tech Memo year storm.7 foot tide 3 LAKE W THALIA Pmp CFS Figure 2. Relationship between maximum pumping rates and WSE in Thalia Creek when a tide gate is installed at the confluence of Thalia Creek and Lake Windsor According to GIS information, most homes along Thalia Creek are situated beyond the 8 foot contour. A WSE of 7.6 feet when there is a tide of.7 feet and a 10- year storm event results in the creek rising up into many yards and causing the residents to be alarmed. A high tide of 6 feet coupled with a 10- year storm causes the WSE to approximately 8 feet. According to the model, the size of the pump station affects the water level of the lake, but does not significantly affect the peak WSE of the Windsor Woods canal or the piped system feeding the canal. It does reduce the amount of time the streets remain flooded from several hours to ½ hour. These calculations are based on a constant tailwater elevation simulating a high tide event, and do not take into account the normal ebb and flow of tides. As such, the optimal pumping rate is calculated to be 60 cfs (3 pumps with a rate 20 cfs each) which lowers the lake level adequately to allow the system to drain, and does not significantly increase the WSE of Thalia Creek. Conclusion A pump station at the confluence of Thalia Creek and Lake Windsor will not eliminate flooding in the streets of Windsor Woods completely, but will decrease the total time of flooding. As storms become more intense and tides become higher as predicted by studies on sea level rise, some residents along Thalia Creek who will claim to have never seen water levels as high as previously may perceive that the new pump station to be the cause. Though the presence of a 60 cfs pump station increases the WSE at Thalia Creek, it is not a significant increase. Nonetheless, the pump station construction and presence may create an expectation of improvement in the 5

6 Optional Services Tech Memo existing conditions. When this improvement is not forthcoming for their particular area, and in fact appears to be worse, residents in this area may perceive that the pump station is the cause. Moreover, residents in Windsor Woods will expect major improvements, and for the most part a pump station in Lake Windsor will improve the drainage in the Windsor Woods neighborhoods, but flooding will still occur, albeit not as long or as much. 6

7 JUNCTION NODE " ) LINK " ) " ) I 26 L_695A L_268/Pres2 L_620801/Rose3 Link LW Fire Station " ) Lake Windsor L_805 ^ L_301 L_237/Pres10 L_755A Windsor Woods C an al " ) Tr l mont R d Lake Trashmore Silina L_137 Old F org 178 e S Rose a S Pl az L_885b # Link279 " ) L_c Bow Cre e # k Bo w ,80 Feet WINDSOR WOODS WATERSHED STUDY XP SWMM LINKS AND NODES Bow Creek Cr ee k

8 Optional Services Tech Memo Appendix A1 Plan Views, Profile Views, and Dynamic Long Section Views for 2-year Storm

9 Appendix A1-2 year.7 foot tide PLAN VIEWS Existing Conditions Tide gates at I-26 1

10 Appendix A1-2 year.7 foot tide Tide gates at confluence of Thalia Creek and Windsor (Max Pump Rate = 60 cfs) 2

11 Flow (cfs) Hydrology Rates Appendix A1-2 year.7 foot tide Node [Max Flow = ] Rainfall Total Flow Thu Jul AM 6AM 9AM 12PM 3PM 6PM 9PM 12 Fri 3AM 6AM 9AM 12PM 3PM 6PM 9PM 13 Sat Rainfall Distribution for 2 year storm 3

12 Stage (ft) Overflow (ft^3) Appendix A1-2 year.7 foot tide PROFILE PLOTS LAKE WINDSOR Existing Conditions Node - 730LW [Max Stage = 0.316][Max Overflow = ] Stage Overflow Thu Jul AM 6AM 9AM 12PM 3PM 6PM 9PM 12 Fri 3AM 6AM 9AM 12PM 3PM 6PM 9PM 13 Sat

13 Stage (ft) Overflow (ft^3) Appendix A1-2 year.7 foot tide Tide gates at I-26 Node - 730LW [Max Stage = 0.828][Max Overflow = ] Stage Overflow Thu Jul AM 6AM 9AM 12PM 3PM 6PM 9PM 12 Fri 3AM 6AM 9AM 12PM 3PM 6PM 9PM 13 Sat Tide gates at confluence of Thalia Creek and Windsor Lake (MAX PUMP RATE = 60 cfs) 5

14 Appendix A1-2 year.7 foot tide DYNAMIC LONG SECTION VIEWS THALIA CREEK Existing Conditions I-26 Culverts Tide gates at I-26 (MAX PUMP RATE = 360) 6

15 Appendix A1-2 year.7 foot tide Tide gates at confluence of Thalia Creek and Windsor Lake (MAX PUMP RATE = 60 cfs) WINDSOR WOODS CANAL Existing Conditions Tide gates at I-26 (MAX PUMP RATE = 360 cfs) 7

16 Appendix A1-2 year.7 foot tide Tide gates at confluence of Thalia Creek and Windsor Lake (MAX PUMP RATE = 60 cfs) 8

17 Optional Services Tech Memo Appendix A2 Plan Views, Profile Views, and Dynamic Long Section Views for 10-year Storm

18 Appendix A2-10 year.7 foot tide PLAN VIEWS Existing Conditions Tide gates at I-26 1

19 Flow (cfs) Hydrology Rates Appendix A2-10 year.7 foot tide Tide gates at confluence of Thalia Creek and Windsor Node [Max Flow = ] 0 Rainfall Total Flow Thu Jul AM 6AM 9AM 12PM 3PM 6PM 9PM 12 Fri 3AM 6AM 9AM 12PM 3PM 6PM 9PM 13 Sat Rainfall Distribution for 10 year storm 2

20 Stage (ft) Stage (ft) Overflow (ft^3) Overflow (ft^3) Appendix A2-10 year.7 foot tide PROFILE PLOTS LAKE WINDSOR Node - 730LW [Max Stage = 7.15][Max Overflow = ] Stage Overflow Thu Jul AM 6AM 9AM 12PM 3PM 6PM 9PM 12 Fri 3AM 6AM 9AM 12PM 3PM 6PM 9PM 13 Sat Existing Conditions Node - 730LW [Max Stage = 3.795][Max Overflow = ] Stage Overflow Thu Jul AM 6AM 9AM 12PM 3PM 6PM 9PM 12 Fri 3AM 6AM 9AM 12PM 3PM 6PM 9PM 13 Sat Tide gates at I-26 3

21 Stage (ft) Stage (ft) Overflow (ft^3) Overflow (ft^3) Appendix A2-10 year.7 foot tide Node - 730LW [Max Stage = 3.563][Max Overflow = ] Stage Overflow Thu Jul AM 6AM 9AM 12PM 3PM 6PM 9PM 12 Fri 3AM 6AM 9AM 12PM 3PM 6PM 9PM 13 Sat Tide gates at confluence of Thalia Creek and Windsor Lake (MAX PUMP RATE = 60 cfs) Node - 730LW [Max Stage = 3.087][Max Overflow = ] Stage Overflow Thu Jul AM 6AM 9AM 12PM 3PM 6PM 9PM 12 Fri 3AM 6AM 9AM 12PM 3PM 6PM 9PM 13 Sat Tide gates at confluence of Thalia Creek and Windsor Lake (MAX PUMP RATE = 90 cfs)

22 Stage (ft) Overflow (ft^3) Appendix A2-10 year.7 foot tide Node - 730LW [Max Stage = 1.259][Max Overflow = ] Stage Overflow Thu Jul AM 6AM 9AM 12PM 3PM 6PM 9PM 12 Fri 3AM 6AM 9AM 12PM 3PM 6PM 9PM 13 Sat Tide gates at confluence of Thalia Creek and Windsor Lake (MAX PUMP RATE = 360 cfs) 5

23 Appendix A2-10 year.7 foot tide DYNAMIC LONG SECTION VIEWS THALIA CREEK Existing Conditions I-26 Culverts Tide gates at I-26 (MAX PUMP RATE = 360) 6

24 Appendix A2-10 year.7 foot tide Tide gates at confluence of Thalia Creek and Windsor Lake (MAX PUMP RATE = 60 cfs) Tide gates at confluence of Thalia Creek and Windsor Lake (MAX PUMP RATE = 90 cfs) Tide gates at confluence of Thalia Creek and Windsor Lake (MAX PUMP RATE = 360 cfs) 7

25 Appendix A2-10 year.7 foot tide WINDSOR WOODS CANAL Existing Conditions Tide gates at I-26 (MAX PUMP RATE = 360 cfs) Tide gates at confluence of Thalia Creek and Windsor Lake (MAX PUMP RATE = 60 cfs) 8

26 Appendix A2-10 year.7 foot tide Tide gates at confluence of Thalia Creek and Windsor Lake (MAX PUMP RATE = 90 cfs) Tide gates at confluence of Thalia Creek and Windsor Lake (MAX PUMP RATE = 360 cfs) 9

27 Optional Services Tech Memo Appendix A3 Plan Views, Profile Views, and Dynamic Long Section Views for 25-year Storm

28 Appendix A3-25 year.7 foot tide PLAN VIEWS Existing Conditions Tide gates at I-26 1

29 Appendix A3-25 year.7 foot tide Tide gates at confluence of Thalia Creek and Windsor (Max Pump Rate = 60cfs) Tide gates at confluence of Thalia Creek and Windsor (Max Pump Rate = 90cfs) 2

30 Flow (cfs) Hydrology Rates Appendix A3-25 year.7 foot tide Node [Max Flow = ] Rainfall Total Flow Thu Jul AM 6AM 9AM 12PM 3PM 6PM 9PM 12 Fri 3AM 6AM 9AM 12PM 3PM 6PM 9PM 13 Sat Rainfall Distribution for 10 year storm 3

31 Stage (ft) Stage (ft) Overflow (ft^3) Overflow (ft^3) Appendix A3-25 year.7 foot tide PROFILE PLOTS LAKE WINDSOR Node - 730LW [Max Stage = 7.67][Max Overflow = ] 8 Stage Overflow Thu Jul AM 6AM 9AM 12PM 3PM 6PM 9PM 12 Fri 3AM 6AM 9AM 12PM 3PM 6PM 9PM 13 Sat Existing Conditions Node - 730LW [Max Stage = 6.037][Max Overflow = ] Stage Overflow Thu Jul AM 6AM 9AM 12PM 3PM 6PM 9PM 12 Fri 3AM 6AM 9AM 12PM 3PM 6PM 9PM 13 Sat Tide gates at I-26

32 Stage (ft) Stage (ft) Overflow (ft^3) Overflow (ft^3) Appendix A3-25 year.7 foot tide Node - 730LW [Max Stage = 5.518][Max Overflow = ] Stage Overflow Thu Jul AM 6AM 9AM 12PM 3PM 6PM 9PM 12 Fri 3AM 6AM 9AM 12PM 3PM 6PM 9PM 13 Sat Tide gates at confluence of Thalia Creek and Windsor Lake (MAX PUMP RATE = 60 cfs) Node - 730LW [Max Stage =.966][Max Overflow = ] Stage Overflow Thu Jul AM 6AM 9AM 12PM 3PM 6PM 9PM 12 Fri 3AM 6AM 9AM 12PM 3PM 6PM 9PM 13 Sat Tide gates at confluence of Thalia Creek and Windsor Lake (MAX PUMP RATE = 90 cfs) 5

33 Appendix A3-25 year.7 foot tide DYNAMIC LONG SECTION VIEWS THALIA CREEK Existing Conditions I-26 Culverts Tide gates at I-26 (MAX PUMP RATE = 360) 6

34 Appendix A3-25 year.7 foot tide Tide gates at confluence of Thalia Creek and Windsor Lake (MAX PUMP RATE = 60 cfs) Tide gates at confluence of Thalia Creek and Windsor Lake (MAX PUMP RATE = 90 cfs) 7

35 Appendix A3-25 year.7 foot tide WINDSOR WOODS CANAL Existing Conditions Tide gates at I-26 (MAX PUMP RATE = 360 cfs) Tide gates at confluence of Thalia Creek and Windsor Lake (MAX PUMP RATE = 60 cfs) 8

36 Appendix A3-25 year.7 foot tide Tide gates at confluence of Thalia Creek and Windsor Lake (MAX PUMP RATE = 90 cfs) 9

37 Optional Services Tech Memo Appendix A Plan Views, Profile Views, and Dynamic Long Section Views for 50-year Storm

38 Appendix A- 50 year.7 foot tide PLAN VIEWS Existing Conditions Tide gates at I-26 1

39 Flow (cfs) Hydrology Rates Appendix A- 50 year.7 foot tide Tide gates at confluence of Thalia Creek and Windsor (Max Pump Rate = 60 cfs) Node [Max Flow = ] Rainfall Total Flow 0 11 Thu Jul AM 6AM 9AM 12PM 3PM 6PM 9PM 12 Fri 3AM 6AM 9AM 12PM 3PM 6PM 9PM 13 Sat Rainfall Distribution for 50 year storm 2

40 Stage (ft) Stage (ft) Overflow (ft^3) Overflow (ft^3) Appendix A- 50 year.7 foot tide PROFILE PLOTS LAKE WINDSOR Node - 730LW [Max Stage = 8.028][Max Overflow = ] 8 Stage Overflow Crown Elevation = Thu Jul AM 6AM 9AM 12PM 3PM 6PM 9PM 12 Fri 3AM 6AM 9AM 12PM 3PM 6PM 9PM 13 Sat Existing Conditions Node - 730LW [Max Stage = 7.07][Max Overflow = ] Stage Overflow Thu Jul AM 6AM 9AM 12PM 3PM 6PM 9PM 12 Fri 3AM 6AM 9AM 12PM 3PM 6PM 9PM 13 Sat Tide gates at I-26 3

41 Stage (ft) Overflow (ft^3) Appendix A- 50 year.7 foot tide Node - 730LW [Max Stage = 6.92][Max Overflow = ] 7 Stage Overflow Thu Jul AM 6AM 9AM 12PM 3PM 6PM 9PM 12 Fri 3AM 6AM 9AM 12PM 3PM 6PM 9PM 13 Sat Tide gates at confluence of Thalia Creek and Windsor Lake (MAX PUMP RATE = 60 cfs)

42 Appendix A- 50 year.7 foot tide DYNAMIC LONG SECTION VIEWS THALIA CREEK Existing Conditions I-26 Culverts Tide gates at I-26 (MAX PUMP RATE = 360) 5

43 Appendix A- 50 year.7 foot tide Tide gates at confluence of Thalia Creek and Windsor Lake (MAX PUMP RATE = 60 cfs) 6

44 Appendix A- 50 year.7 foot tide WINDSOR WOODS CANAL Existing Conditions Tide gates at I-26 (MAX PUMP RATE = 360 cfs) Tide gates at confluence of Thalia Creek and Windsor Lake (MAX PUMP RATE = 60 cfs) 7

45 Optional Services Tech Memo Appendix B1 Water Surface Elevations for 2-year Storm

46 Table 1. Water surface elevations at each system trunk calculated by XPSWMM for 2-year storm 2 year.7 ft tide 2 year 3 ft tide 2 year 1 ft tide Model Used (XP) WWB2yrPExist WWB_2yrSOUTH_p80 WWB_2yrX2_p20 WWB2yrPExist WWB2yrPExist Exist Phase1/2 (I-26) Phase1/2 Confluence Exist with 3 ft tide Exist with 1 ft tide Link Flow (cfs) WSE (ft) Flooded Flow (cfs) WSE (ft) Flooded Flow (cfs) WSE (ft) Flooded Flow (cfs) WSE (ft) Flooded Flow (cfs) WSE (ft) Flooded TCN -L_695A Culverts Link TCM-L_ b L_ TCS-Lc LW-node730LW WWCW-L_ WWCE-L_755A L237/Pres L_268/Pres hr min min min DS Rose-Link hr hr hr hr hr. US Rose- L620801/Rose3 PUMPS hr hr min min min 80cfs 3 20 cfs

47 Optional Services Tech Memo Appendix B2 Water Surface Elevations for 10-year Storm

48 Table 1. Water surface elevations at each system trunk calculated by XPSWMM for 10-year storm.7 ft tide 10 year.7 ft tide Model Used (XP) WWC10YRPEXIST WWB_10YRSouth_P80 WWB_10yrX2_p30 WWC10YR X2_p20 WWB_10yrX2_p80 Exist Phase1/2 (I-26) Phase1/2 Confluence Phase1/2 Confluence Phase1/2 Confluence Link Flow (cfs) WSE (ft) Flooded (h) Flow (cfs) WSE (ft) Flooded (h) Flow (cfs) WSE (ft) Flooded (h) Flow (cfs) WSE (ft) Flooded (h) TCN -L_695A Flow (cfs) WSE (ft) Flooded (h) Culverts Link TCM-L_ b L_ TCS-Lc LW-node730LW WWCW-L_ WWCE-L_755A L237/Pres L_268/Pres DS Rose-Link US Rose- L620801/Rose3 PUMPS Max 3 cfs 85 cfs 3 30 cfs 3 20 cfs 85 cfs

49 Table 2. Water surface elevations at each system trunk calculated by XPSWMM for 10-year storm 6 ft tide 10 year 6 ft tide Model Used (XP) WWC10YRPEXIST WWB_10YRSouth_P80 WWB_10yrX2_p30 WWC10YRPEXIST Exist Phase1/2 (I-26) Phase1/2 Confluence Phase1/2 Confluence Link Flow (cfs) WSE (ft) Flooded (h) Flow (cfs) WSE (ft) Flooded (h) Flow (cfs) WSE (ft) Flooded (h) Culverts Link Flow (cfs) WSE (ft) Flooded (h) L_ LW-node730LW WWCE-L_755A DS Rose-Link PUMPS Max 3 cfs 85 cfs 3 30 cfs 3 20 cfs

50 Optional Services Tech Memo Appendix B3 Water Surface Elevations for 25-year Storm

51 Table 1. Water surface elevations at each system trunk calculated by XPSWMM for 25-year storm.7 ft tide 25 year.7 ft tide Model Used (XP) WWB_25YRpeXIST WWB_25yrSOUTH_P80 WWB_25yrX2_P30 WWB_25yrX2_P20 Exist Phase1/2 (I-26) Phase1/2 Confluence Phase1/2 Confluence Link Flow (cfs) WSE (ft) Flooded (h) Flow (cfs) WSE (ft) Flooded (h) Flow (cfs) WSE (ft) Flooded (h) TCN -L_695A Flow (cfs) WSE (ft) Flooded (h) Culverts Link TCM-L_ b L_ TCS-Lc LW-node730LW WWCW-L_ WWCE-L_755A L237/Pres L_268/Pres DS Rose-Link US Rose- L620801/Rose3 PUMPS Max 3 cfs 85 cfs 3 30 cfs 3 20 cfs