防洪系統(tǒng)外文翻譯

1、<p>　　3500單詞，18500英文字符,5800漢字</p><p>　　出處：Roman M E, Bender T W. Upper Potomac Industrial Park Flood Control System[C]//World Water & Environmental Resources Congress 2003. 2003: 1-8.</p><

2、;p><b>　　附錄一</b></p><p>　　UPPER POTOMAC INDUSTRIAL PARK FLOOD CONTROL SYSTEM</p><p>　　Mary E. Roman, PE 1 and Thomas W. Bender, PE 2</p><p>　　McCrone Inc., 20 Ridgely

3、Avenue, Annapolis, MD 21401; PH (410) 267-8621;FAX (410)</p><p>　　237-9932; email: mroman@mccrone-inc.com</p><p>　　Allegany County, Department of Public Works, 701 Kelly Road, Suite 300, Cumberl

4、and, MD21502; PH (301) 777-5933; FAX (301) 777-2001; email: tbender@allconet.org</p><p>　　BACKGROUND</p><p>　　During Hurricane Fran, which occurred in September 1996, three buildings in the Uppe

5、r Potomac Industrial Park (UPIP) located near Cumberland in Allegany County, Maryland experienced flooding to depths of approximately eight inches to one foot. The flooding was caused by overtopping of the banks of the N

6、orth Branch of the Potomac River to an approximate elevation of 630.5. This level exceeds the predicted Federal Emergency Management Agency’s (FEMA’s) 100-year floodplain elevation of 629.2. Th</p><p>　　$

7、500,000 a clothing manufacturer which employs over 500 people. The majority of the damages consisted of fabrics used to construct clothing.</p><p>　　Allegany County was also hit by a major flooding event in

8、January. Both Hurricane Fran and the January flooding event received federal disaster designation. As a result, the Governor of Maryland formed the Western Maryland Flood Mitigation Task Force. The goal of the task force

9、 was to provide immediate and long-range improvements for floodprone areas in western Maryland. The engineering design and construction of improvements at UPIP is one of several projects that Allegany County is proceedin

10、g </p><p>　　The challenge presented at UPIP is the fact that the buildings were built higher than the FEMA floodplain to prevent flooding, and yet, Hurricane Fran which was not even at a 100-</p><

11、p>　　year event, flooded three of the buildings. Further, the flooded business indicated that they may move out of the state, which represents a significant threat to the economic base of the County. This following sec

12、tions describe a summary of the detailed hydrologic and hydraulic analyses that were conducted to determine the potential cause of the flooding. Following these</p><p>　　sections, the design of the flood con

13、trol measures are also summarized.</p><p><b>　　HYDROLOGY</b></p><p>　　A review of the available hydrologic data was conducted to determine discharge and elevation information for the

14、 North Branch of the Potomac River in the vicinity of UPIP. The focus of the review was on Hurricane Fran and the associated discharges and water surface elevations at UPIP and the nearby gaging stations. A hydrologic an

15、alysis was not conducted as part of this study. The data sources included the following:</p><p>　　Flood Insurance Study (FIS) for Allegany County</p><p>　　WEB sites for the United States Geologi

16、cal Survey (USGS) and the National Weather Service (NWS)</p><p>　　Telephone Conversations with the USGS, NWS and the U.S. Army Corps of Engineers (COE)</p><p>　　Rainfall and gaging station infor

17、mation from Allegany County</p><p>　　FEMA Flood Insurance Study</p><p>　　The Federal Emergency Management Agency performed a hydrologic analysis for the North Branch of the Potomac River. Discha

18、rges were determined using a log-Pearson Type III analysis as outlined in the U. S. Water Resources Council Bulletin No. 17. The data for this analysis were obtained from three USGS gaging stations (e.g., Cumberland, Pin

19、to, and Luke). FEMA’s analysis considers the effects of the Jennings Randolph (i.e., Bloomington) and Savage River flood control reservoirs. However, it is not</p><p>　　Table 1. FEMA Discharges for the North

20、 Branch of the Potomac River</p><p>　　Hurricane Fran</p><p>　　On September 7, 1997, Hurricane Fran deposited approximately 3.5–4.6 inches of rain in the Cumberland, Maryland area. According to a

21、 bulletin from the COE, precipitation for this event varied widely–from four to eight inches with reports of 14 inches–throughout the Potomac River basin. Based on our search for available rainfall data, the nearest rain

22、fall recording stations, Martinsburg WV, Elkins, WV, and Morgantown, WV, reported rainfall amounts of 3.16, 2.52, and 1.08 inches, respectively. The</p><p>　　4.63 inches. In comparison, rainfall estimates fo

23、r Allegany County are 4.7, 5.7, 6.2, and 7.4 inches for the 10-, 50-, 100-, and 500-year events.</p><p>　　Although the rainfall amounts are less than the predicted 50-year rainfall, Hurricane Fran resulted i

24、n record water surface elevations on the North Branch of the Potomac River in the vicinity of the Upper Potomac Industrial Park. In addition, the gaging stations in the area recorded maximum discharges that ranged from l

25、ess than the 50-year event to greater than the 100-year event. The maximum discharges recorded at the local gaging stations are provided in the table below.</p><p>　　Table 2. Hurricane Fran Discharges</p&

26、gt;<p>　　The town of Cumberland experienced severe flooding in January of 1996 as well. The flooding was attributed to a combination of rain and snowmelt. Approximately 2.19 inches of rain was recorded at the Rubb

27、le Landfill. The flooding along Wills Creek was noted as a storm of record with the flow reaching 45,000 cfs at the gaging station. This flow is greater than the 500-year discharge (32,672 cfs) and is three times as much

28、 as the discharge that occurred on Wills Creek during Hurricane Fran. Due to</p><p>　　2.3 Release Rate Verification</p><p>　　As mentioned previously, two major flood control reservoirs exist ups

29、tream of the UPIP. Release rate protocol during storm events consists of monitoring levels the Luke gaging station to determine when the level reaches the NWS High Flood Stage. When the levels approach the flood stage, t

30、he operators hold back discharge from the reservoirs. According to Richard Oloin, Chief of the Water Control and Quality Section, U.S., Army Corps of Engineers (COE), the maximum allowable release rate for these</p>

31、;<p>　　One of the initial theories to support the high water surface elevations is that upstream flood control reservoirs exceeded the allowable release rates during Hurricane Fran. Based on data provided by the C

32、OE, the release rates were 4,320 cfs and 7,741 cfs on September 7, 1996 at the Savage Dam and the Jennings Randolph Lake, respectively. The maximum discharge recorded at the Luke Station, which is just downstream of the

33、two reservoirs, was 11,800 cfs. Based on the Summary of Discharge Table in</p><p><b>　　the FIS.、</b></p><p>　　HYDRAULICS</p><p>　　Using discharge information gleaned fro

34、m the above analysis, hydraulic models were developed using the U.S. Army Corps of Engineers HEC-RAS computer program to estimate</p><p>　　water surface elevations in the vicinity of the Upper Potomac Indus

35、trial Park during Hurricane Fran.</p><p>　　FEMA Model</p><p>　　First, an updated FEMA model was created using the following data:</p><p>　　Cross-section data were obtained from rece

36、nt survey information. Topographic maps were generated from aerial photographs which were flown in 1998. The bottom of the North Branch channel was obtained by extrapolating the side-slopes to the inverts as noted in the

37、 FEMAstudy.</p><p>　　Manning’s n values of 0.08 for the overbanks and 0.03 for the channel were obtained from the FEMA study.</p><p>　　Starting water surface elevations were obtained from the FE

38、MA study.</p><p>　　Channel bank stations were at slope breaks.</p><p>　　The FEMA cross-section data and the data from the recent topographic survey were compared in the vicinity of the UPIP to d

39、etermine whether ground conditions for the FEMA study are consistent with present conditions. Based on cross section plots of Section No. 126, the FEMA ground elevations are nearly identical to the 1998 topographic infor

40、mation. However, it should be noted that buildings were not included in the HEC-2 model either on the ground card data (e.g., GRs) or by using effective flow </p><p>　　The results of the model compare favora

41、bly with the FEMA elevations. The approximate 100- year FEMA elevation is 629.17 in the vicinity of the UPIP and the corresponding HEC-RAS elevation is 629.24. A table of water surface elevations is presented in Appendix

42、 A.</p><p>　　Calibration to Hurricane Fran</p><p>　　Both the regulatory FEMA floodplain elevations and the HEC-RAS FEMA model predict lower elevations than occurred during Hurricane Fran. The Hu

43、rricane Fran highwater elevation measured at UPIP was 630.5, while the FEMA predicts closer to 629.2. The difference in water surface elevation may be attributable to temporary localized downstream blockages such as</

44、p><p>　　fallen branches or trees; however, there is no way to model this scenario without detail on the blockage. Second, FEMA analyses are based on existing land use conditions discharges from over 10 years ag

45、o. Intense development in the area may result in higher discharges. According to County representatives, development in the watershed has not been significant. Therefore, without evidence of other factors, calibration of

46、 the HEC-RAS model was performed to obtain results closer to the highwater ele</p><p>　　First, discharges from the Pinto gaging station were extrapolated downstream. The Pinto gaging station recorded a maxim

47、um discharge of 26,200 cfs which is slightly higher than the 100-year FEMA discharge of 25,800 cfs at Pinto. The FEMA 100-year discharge at the UPIP is 27,000 cfs. Using the ratio of FEMA discharges at Pinto to those at

48、Cumberland, the discharge was extrapolated downstream to be 27,500 cfs.</p><p>　　Next, efforts were made to increase the HEC-RAS water surface elevations to better match the highwater elevations from Hurrica

49、ne Fran. The calibration efforts consisted of adding ineffective flow areas and increasing Manning’s n values as described below.</p><p>　　To better model effective flow in the vicinity of the UPIP, encroach

50、ments were added to the hydraulic model. The effective flow option of HEC-RAS was used to block out areas of ineffective flow which include the floodplain areas located beyond the existing buildings and the industrial pa

51、rk access road fill. The effective flow lines are shown on the floodplain map which is included in the back pocket of this report. This change to the HEC-RAS model resulted in only a slight increase in water surf</p&g

52、t;<p>　　Manning’s n values were then increased. Manning’s n values were increased from 0.03 and 0.09 to 0.041 and 0.12 in the channel and overbank, respectively. These changes resulted in a HECRAS model that gener

53、ated an elevation of 630.5 in the vicinity of UPIP (i.e., at cross- section 132).</p><p>　　POTENTIAL IMPROVEMENT MEASURES</p><p>　　Although the rainfall amounts were not indicative of a 100-year

54、 event, the results of the hydraulic analysis appear reasonable that the UPIP would be flooded given the flows at the gaging station. The next step was to identify potential measures to reduce the risk of flooding at the

55、 UPIP. Below is a list of potential flood control improvement measures considered for</p><p>　　implementation along with the pros and cons of selecting each measure.</p><p>　　Table 3. Summary of

56、 Potential Flood Control Improvement Measure</p><p>　　Although several of the nonstructural measures (e.g., flood warning and internal realignment) may have been feasible, it was decided that a structural me

57、asure, the flood control berm, should be implemented. This solution is the only solution that eliminates flooding to the businesses and ensures that the business remains in the County, which is important to the County’s

58、economic development base. The selection of this measure hinged on obtaining a</p><p>　　$710,000 Hurricane Fran related economic development grant from the U.S. Economic</p><p>　　Deve

59、lopment Administration. As mentioned previously, the State is also providing funds through the flood hazard task force, but more is needed to construct the flood control measure. Once the general agreement to award the g

60、rant had been attained, the design of the flood control measure commenced.</p><p>　　FLOODWALL/LEVEE DESIGN</p><p>　　Determine Design Criteria</p><p>　　Typically, the top of a flood

61、control structure such as a levee is set at one to two feet above the predicted 100-year or 500-year water surface elevation. However, in the case of the UPIP, these elevations were exceeded during Hurricane Fran which w

62、as likely to be less than a 50- year event based on rainfall amounts. Based on our analysis, there is no obvious cause (e.g., differing topographic conditions, high release rates) for the high water surface elevations. T

63、herefore, the appropriate desi</p><p>　　It was recommended that the County consider building the levee/floodwall to at least a height of 632.0. This elevation is 1.5 feet greater than the recent flood event.

64、 Using the calibrated model, a discharge of 31,250 cfs would be contained within the levee. Contributing to the decision making process was that the County decided that the levee/floodwall should be certified by FEMA, if

65、 possible. This requirement was subsequently included in the EDA grant awarded for this project. FEMA requires th</p><p>　　Design criteria outlined in the U.S. Army Corps of Engineers’ Design and Constructio

66、n for Levees (EM1110-2-1913) was utilized for this project, in particular for the design of the floodwall, levee, stormdrain pipes through the levee, and for the pumps.</p><p>　　Floodwall/Levee Design</p&

67、gt;<p>　　The majority of the flood control structure consists of an earthen berm. At the upstream end of the berm and near the downstream end, a concrete floodwall is proposed due to limited space to tie out the g

68、rading. Side-slopes of the proposed berm are at 2:1. The proposed floodwall</p><p>　　is a concrete wall. The maximum height of the proposed floodwall is nine-feet. The maximum height of the proposed berm is

69、fourteen-feet. The top elevation of the upstream section of the proposed combination floodwall berm is 632.50. The downstream section of the proposed combination floodwall berm is 630.50. In addition, a floodwall/berm is

70、 proposed along a tributary which runs parallel to the Upper Potomac Industrial Park Street at the north end of the industrial park. This section of the flood</p><p>　　Interior Drainage</p><p>　

71、　With the introduction of the berm/floodwall, the internal drainage area, which once flowed into the North Potomac River, had to be redirected. The internal drainage area created by the flood control structure consists o

72、f approximately 39 acres of the Upper Potomac Industrial Park. The Industrial Park, which has gradual cross slopes of less than one percent, generally drains towards the flood control structure via overland flow, shallow

73、 grassed swales, and limited closed storm drainage.</p><p>　　This internal drainage was redirected into proposed grassed swales and proposed storm drain systems which outfall into three storm water managemen

74、t ponds. All three ponds will have water quality benefits by the creation of a shallow marsh area below the outfall pipe elevation.Stormdrain systems were designed to convey the 100-year event. Under normal conditions, t

75、he ponds drain to the North Branch by gravity flow. In the event of high tailwater on the North Branch, flap gates will close and the </p><p>　　The Rational methodology was used to compute flows. HDPE pipe w

76、as proposed to reduce project costs. Hydraulic gradient computations were prepared utilizing Maryland State Highway methodology.</p><p>　　The hydraulic information for this site is calculated based on two po

77、ssible scenarios 1) the 100-year storm occurs and the primary storm drain system discharges the storm runoff to the North Branch of the Potomac River and 2) the 100-year storm occurs and the water surface elevation in th

78、e North Branch of the Potomac River will not allow for the primary storm drain system to gravity flow to the Potomac River. For scenario number one, the primary storm drain</p><p>　　system will function as a

79、 stand-alone system. For scenario number two, the primary storm drain system needs to be augmented with a pumping system to discharge the storm water to the North Branch of the Potomac River. Because of these two possibl

80、e scenarios, the hydraulic gradient calculations were computed for 1) no pumps (only the storm drain system), and 2) for the pumps being activated in conjunction with the storm drain system.</p><p>　　As dire

81、cted by Allegany County, when the flow in the North Branch of the Potomac River reaches the predicted 2-year water surface elevation, it is assumed that the gravity storm drain system will be closed by flap gates to rest

82、rict back flow from the North Branch of the Potomac River from entering the site. The pumps will discharge at rates of 5000 gallons per minute (gpm) (i.e., 11 cubic feet per second (cfs)) for Pond A and 8000 gpm (i.e., 1

83、7 cfs) for Pond C</p><p>　　Pump Design</p><p>　　The pumping of stormwater normally requires a pump that can pump large volumes of water at a relatively low head. To pump the stormwater out of th

84、e ponds, Flypt vertical mixed flow pumps were selected. These types of pumps do not need to be primed and they do not need a separate dry well which would have necessitated a larger, more costly, structure.</p>&l

85、t;p>　　The pump unit consist of a solids handling impeller and a submersible motor. A diffuser with guide vanes is used to stabilize the discharge flow. The diffuser is used in lieu of a centrifugal pump valve. The pum

86、p impeller is protected by a mesh screen with 2 inch openings. The impeller passes any solid which gets past the screen. The 24-inch discharge pipe is connected directly to the discharge column. The discharge pipe is ins

87、talled over the levee.</p><p>　　The pumps are installed 15 foot square pre-cast concrete structures. The pumps turn on when the pond reaches the estimated 2-year water surface elevation. The pumps turn off w

88、hen the pond discharge pipes are empty. The pumps require five feet of submergence. The pumps are controlled by a float in the pond and a secondary float in the wet well which is set one foot higher that the float in the

89、 pond. This emergency flat also activates a high water alarm and telephone dialer.</p><p>　　Resulting Water Surface Elevations in the Industrial Park</p><p>　　The stormdrain system was designed

90、to convey the 100-year event during both gravity and</p><p>　　pump flows. Some ponding at the inlets occurs during pump flows. Refer to the table below for a summary of the hydraulic gradient information for

91、 system number one (Pond A) and system number two (Pond B and Pond C). During the pumping condition, the minimum freeboard from the first floors of the buildings during the pumping scenario is 0.6 feet.</p><p&

92、gt;　　Table 4 – Maximum Hydraulic Gradient Elevations</p><p>　　FEMA REVIEW AND CERTIFICATION</p><p>　　Since none of the structures being protected by the proposed floodwall/berm are below the FEM

93、A 100-year floodplain elevation, certification of the levee is not required. However, the Economic Development grant required certification. Therefore, a Conditional Letter of Map Revision was requested and obtained from

94、 FEMA.</p><p><b>　　SUMMARY</b></p><p>　　Construction of this project is estimated to cost $1.7 million dollars. The money for construction is being provided by grants from the EDA gr

95、ant and State of Maryland with the remainder being provided by the Allegany County. Although only one business was seriously affected by the flooding, seven property owners, who are also located behind the floodwall/leve

96、e permitted the improvements to be located on their properties, without reimbursement.</p><p><b>　　附錄二</b></p><p>　　波多馬克河高級(jí)工業(yè)園區(qū)防洪系統(tǒng)</p><p>　　Mary E. Roman, PE 1 and Thom

97、as W. Bender, PE 2</p><p>　　1 麥克隆公司，里奇利大道 20 號(hào)，安納波利斯，馬里蘭州；PH（410）267-8621；傳真</p><p>　?。?10）237-9932；電子郵件：mroman@mccrone-inc.com</p><p>　　2 阿利根尼縣，公共工程部，凱利路 701 號(hào) 300 室，坎伯蘭，馬里蘭州；PH（30

98、1）777- 5933；傳真（301）777-2001；電子郵件：tbender@allconet.org</p><p><b>　　1 背景</b></p><p>　　在 1996 年 9 月發(fā)生的弗蘭颶風(fēng)期間，三座位于馬里蘭州坎伯蘭郡阿利根尼縣波多 馬克河高級(jí)工業(yè)園區(qū)(UPIP)附近的建筑物見證了深約八英寸到一英尺的洪水。洪水泛濫 的原因是由于河水漫過了海拔