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Estudio hidrolgico e hidrulico
7
9 de octubre de 2006
Federico L. Togni, DirectorPR One, Inc.PO Box 800643Coto Laurel, PR 00780
RE: HOJA DE TRAMITE:ESTUDIO HIDROLOGICO/HIDRAULICO, CLUB PORTOFINO, NAGUABO, PUERTO RICO
Estimado ingeniero Togni:
La siguiente es para someter el estudio hidrolgico e hidrulico final del proyecto de referencia.Se incluyen en este trmite los siguientes documentos:
1. Dos (2) Originales del Informe H/H Club Portofino, Naguabo, PR. 2. Factura # CHE0604.3. Dos (2) Discos Compactos con Modelos Hidrolgicos e Hidrulicos utilizados en el informe.4. Certificacin de Consultor que Complet Estudio.
Note que DRNA requiere los planos topogrficos, secciones transversales, y pluvial finaldebidamente sellados y firmados, incluyendo certificacin (carta) del agrimensor en original.Adems, DRNA requiere una carta original del Dueo que autorice al Ing. Jos L. Irizarry Rosaa completar H/H. Finalmente, se debe proveer con copia de la escritura notarizada de lapropiedad. Estos documentos se deben incluir en las carpetas del H/H (ltima seccin delApndice) y junto con el disco compacto, entregarse a Secretara en el DRNA.
Cordialmente,
Jos Luis Irizarry Rosa, MCE, PEd.b.a. Caribbean Hydrologic Engineers
Jos Luis Irizarry Rosa, MECE, PEYadira L. Ayala Ros, PE
Mansin RealCalle Isabel #205
Coto Laurel, Puerto Rico 00780 -2600Caribbean Hydrologic Engineers
Tel. (787) 848-2075 Fax (787) 848-1562Email: jlipim@jlipim.com
DETENTION POND DESIGN STUDY: CLUB PORTOFINO PROJECT,
SECTOR HUCARES, SANTIAGO Y LIMA WARD, MUNICIPALITY OF NAGUABO, PUERTO RICO
Presented to:
Federico L. Togni, Director PR One, Inc.
PO Box 800643 Coto Laurel, Puerto Rico 00780
October 9, 2006
Jos Luis Irizarry Rosa, MCE, PE
Yadira L. Ayala Ros, PE Mansin Real
205 Calle Isabel Coto Laurel, Puerto Rico 00780-2600
Tel. (787) 848-2075 Hydrologic Studies Hydraulic Studies Fax. (787) 848-1562
Water Resources Management Email: jlipim@jlipim.com
Detention Pond Study, Club Portofino Project, Santiago y Lima Ward, Naguabo, Puerto Rico
Caribbean Hydrologic Engineers i
I. Executive Summary The subject study is part of the design requirements for the proposed Club Portofino in Naguabo, Puerto Rico. The latter consists of the development of a hotel, condo hotel, villas, and sports and service facilities. The project occupies a tract of land of approximately 78.71-acres accessed through a municipal road that conducts to Punta Lima at the Hcares Sector of the Santiago y Lima Ward, Municipality of Naguabo, Puerto Rico. The project is by-passed by two (2) unnamed creeks, one to the West with a basin of about 178.5-acres, and one to the East with about 200.3-acres of watershed area. Both discharge to the Lima Bay which lies to the southeast of the property. To assist in the compliance with the Puerto Rico Planning Board (PRPB) and the Department of Natural and Environmental Resources (DNER) requirements for storm water management, project developer, Eng. Federico Togni, from PR One, Inc., retained our services to evaluate the current and proposed hydrologic conditions of this site, and to determine the corresponding runoff detention system necessary to control excess flows and erosion to be produced by future development. Based on the building distribution, we chose the southeast corner of the property as the ideal location for the detention facilities. The approach will be to develop two (2) independent detention ponds, one for each side of the center ridge that bisects the property. This same divide also applies for the east and west unnamed creeks that travel across the parcel. Therefore each pond will discharge to its corresponding creek just prior their exit from the property. The west pond accounts with a bottom area of 2,558-square meters and a height of 3.75-m. It will be equipped with two (2), 5-ft. X 8-ft. box culvert sections. The east pond includes a 3,226-square meter bottom area with a primary outlet consisting of one (1) box culvert with a 5-ft. X 7-ft. section. Two (2) additional devices, positioned in a multistage structure, are recommended to handle low and intermediate flows. These include an 8-inch diameter pipe positioned at the ponds invert, and two (2), 4-ft. X 5-ft. orifice grates located two (2) feet above the ponds invert. These devices connect to the aforementioned primary outlet structure. Both ponds include side slopes with a 2 Horizontal : 1 Vertical inclination.
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Table of Contents
I. Introduction................................................................................................................ 1 II. Study Description.......................................................................................................2 A. Project Location............................................................................................. 2 B. Existing Topography...................................................................................... 2 C. Water Bodies.................................................................................................. 2 D. Problem Description...................................................................................... 2 E. Study Level.................................................................................................... 3 F. Design Conditions.......................................................................................... 3 G. Scope of Work............................................................................................... 4 H. Project Impact................................................................................................ 4 III. Preliminary Evaluation.............................................................................................. 5 A. Visual Inspection of the Site.......................................................................... 5 B. Review of Previous Studies........................................................................... 5 IV. Applied Methodology and Hydrologic Study............................................................6 A. Rainfall Data.................................................................................................. 6 B. Watershed Limits Definition..........................................................................7 C. Bodies of Water Identification....................................................................... 7 D. Topographic Maps......................................................................................... 7 E. Land Use and Vegetation Cover.................................................................... 7 F. Interception and Infiltration........................................................................... 7 G. Unit Hydrograph............................................................................................ 8 H. Summary of Hydrologic Data....................................................................... 9 I. Initial Hydrologic Results.................................................................. 10
J. Detention Pond Theory................................................................................. 11 K. Detention Pond Parameters............................................................................ 12 L. Final Hydrologic Results............................................................................... 14 V. Conclusions................................................................................................................ 16 VI. Reference................................................................................................................... 17
Detention Pond Study, Club Portofino Project, Santiago y Lima Ward, Naguabo, Puerto Rico
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Table of Contents... VII. Appendix....................................................................................................................18
A. Figures B. Rainfall Distribution, SCS Type II Puerto Rico C. HydroCad Output: Summary of All Rainfall Frequencies and Durations D. HydroCad Output: Detailed Report of Selected Rainfall Frequencies and
Durations E. Project Drawings: Site Plan, Cross Sections and Details F. Certifications and Submittal Documents
Detention Pond Study, Club Portofino Project, Santiago y Lima Ward, Naguabo, Puerto Rico
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List of Tables
Table 1. Rainfall-Frequency Data for Naguabo, Puerto Rico...................................... 6 Table 2. Existing Conditions Simulation: Physiographic Information Summary....... 10 Table 3. Proposed Conditions Simulation: Physiographic Information Summary...... 10 Table 4. Hydrologic Results Summary: Existing Conditions. 10 Table 5. Hydrologic Results Summary: Proposed Conditions.... 11 Table 6. Summary of Pond and Outlet Parameters: West Portofino Pond.................. 13 Table 7. Summary of Pond and Outlet Parameters: East Portofino Pond.................. 13 Table 8. Hydrologic Results Summary: Proposed Conditions with Ponds............ 14
Detention Pond Study, Club Portofino Project, Santiago y Lima Ward, Naguabo, Puerto Rico
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List of Figures: Appendix A Figure 1. Project Schematic Layout Figure 2. Project Location: USGS Naguabo Topo Quadrangle Figure 3. Aerial Color Photo of the Site Figure 4. Project Location: FEMA Map, Naguabo, PR
Detention Pond Study, Club Portofino Project, Santiago y Lima Ward, Naguabo, Puerto Rico
Caribbean Hydrologic Engineers 1
I. Introduction The subject study is part of the design requirements for the proposed Club Portofino in Naguabo, Puerto Rico. The latter consists of the development of a hotel, condo hotel, villas, and sports and service facilities. The project occupies a tract of land of approximately 78.71-acres accessed through a municipal road that conducts to Punta Lima at the Hcares Sector of the Santiago y Lima Ward, Municipality of Naguabo, Puerto Rico. The project is by-passed by two (2) unnamed creeks, one to the West with a basin of about 178.5-acres, and one to the East with about 200.3-acres of watershed area. Both discharge to the Lima Bay which lies to the southeast of the property. Please refer to Figure 1 for the planned site layout of the project. To assist in the compliance with the Puerto Rico Planning Board (PRPB) and the Department of Natural and Environmental Resources (DNER) requirements for storm water management, project developer, Eng. Federico Togni, from PR One, Inc., retained our services to evaluate the current and proposed hydrologic conditions of this site, and to determine the corresponding runoff detention system necessary to control excess flows and erosion to be produced by future development. This report gathers all the related hydrologic and hydraulic observations, documentation, computer models and results for the subject project. The available information submitted by the Owner and used in this document consisted of site plans of the proposed layout.
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II. Study Description A. Project Location The project is accessed through a municipal road that conducts to Punta Lima at the Hcares Sector of the Santiago y Lima Ward, Municipality of Naguabo, Puerto Rico. It is bounded to the north by the aforementioned municipal road, to the west by various owners, to the east by a PRIDCO property and to the south by the Caribbean Sea. From a hydrologic standpoint, the approximate centroid of the watershed area is located at the North American Datum 1927 coordinates Easting 229,689-m and Northing 39,484-m. A projects site location is included in Figure 2, using the United States Geological Survey (USGS) Topographic Map of the Naguabo Quadrangle (USGS, 1982). B. Existing Topography The existing topographic features of the site can be described as rolling to mountainous as the area is occupied by a pair of ridge formations that downgrade towards the south-southeast. The terrain elevation ranged from 56-m to about one (1) meter near the low lands that connect with the Lima Bay. All elevations are based on the topographic quadrangle of Naguabo, Puerto Rico (USGS, 1982). C. Water Bodies The subject project property accounts with two (2) unnamed creeks. The first lies to the east of the project and includes a hydraulic length of 1,577-meters. The second lies to the west of the property and accounts with a length of 2,088-meters. Both connect to a low land area located towards the south/southeast part of the parcel. The above water bodies eventually discharge to the Caribbean Sea, which lies about 300-meters from the site. D. Problem Description The following items present the problem description of this work.
1. Rule No. 3 of the PRPB, establishes in Section 14.04 that runoff flows produced by the new development shall not exceed the sites discharge in its existing condition. The project design shall consider this requirement in order to effectively handle the future storm sewer system.
2. Rule 13 of the PRPB provides requirements for construction on flood zones.
The project lies outside an AE flood zone identified towards the southeast side of the property (lowlands) according to the Flood Insurance Rate Maps issued by FEMA (April, 2005).
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3. The Department of Natural and Environmental Resources requested that an assessment be completed with regards to the erosion control measures to be deployed during the construction and operation of the project.
E. Study Level This investigation is intended to provide the owner and his consultants, with the necessary tools required to review the possible scope, from a water resources viewpoint, of any site improvements, development and/or construction proposed in this area. The study in general accounts with a preliminary character given that adjustments to the current building layout may occur during the design process, therefore, affecting some of the parameters established in this report. Furthermore, the completion of a hydraulics analysis will be necessary once all culvert and /or bridge locations (as applicable), and fill embankments are defined in the design process. In addition, the owner and his consultants shall use this document and its annex deliverables, at their discretion, to pursue the corresponding federal and state agency endorsements and approvals that are usually required for this type of project. F. Design Conditions The hydrologic and hydraulic design of this project will be based on the following criterion and methodology:
1. Regulatory Documents: the design of the subject work will follow storm sewer management requirements established in the governing rules that apply: Planning Rule No. 3, Reglamento de Lotificacin y Urbanizacin, and Planning Rule No. 13, Reglamento sobre Areas Especiales de Riesgo a Inundacin, all by the Puerto Rico Planning Board (PRPB).
2. Provided Documents: Eng. Federico Togni submitted a group of documents that
included preliminary site plans of the project.
3. Project Overview: the scope of project includes the development of a hotel and residences complex that will occupy a 78.71-acres property.
4. Proposed Runoff Detention System: this study will consider the design of a
detention pond system to attenuate the excess flows produced by the new development. In addition, the ponds will serve as the primary erosion control system of the project during construction and operation. This in order to protect the adjacent lowland from man made produced sedimentation.
5. Proposed Discharge System: the proposed detention ponds will account with
outlet structures that ultimately will connect to the lower reaches of the unnamed creeks that by-pass the properties and immediately discharge to the Caribbean Sea (Lima Bay), after traveling approximately 300-m through lowlands. To account with a free discharge, the outlet elevation of the discarge pipes must be above the
Detention Pond Study, Club Portofino Project, Santiago y Lima Ward, Naguabo, Puerto Rico
Caribbean Hydrologic Engineers 4
2.2-meters mark. The latter is equivalent to the 100-yr flood elevation of the adjacent AE flood zone.
G. Scope of Work The main general goals for this investigation can be summarized in the following scope of work:
1. Determine the hydrological properties of the watershed.
2. Construct a reasonable mathematical model to perform runoff analysis
simulations for these watersheds, including existing and proposed conditions.
3. Construct a reasonable mathematical model to perform storage and outlet structure design and analysis for the required detention pond. This activity includes the selection of the maximum required storage volume, an assessment on ponds location, materials and geometry.
H. Project Impact The proposed Club Portofino project is currently in the permitting process with local and federal agencies. It is expected to fill a current demand for eco-sensitive, programmed tourist and residential development in the area. Furthermore, the project is also expected to have a positive economic impact in the zone, as several direct and indirect jobs will be required for its construction and operation.
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III. Preliminary Evaluation A. Visual Inspection of the Site A number of field visits were performed for this Project. These were intended to determine the current land use, topography, water bodies, runoff contributors, and proposed project characteristics involved in this study. These findings can be summarized as follows:
1. The site currently corresponds to a vacant tract of land. It is mostly covered by brush, pasture and grass.
2. There are two (2) unnamed creeks that bypass the project. Their channels
account with dense vegetative cover with few stones and cobbles along their beds. They both discharge to the Lima Bay (Caribbean Sea).
Please refer to Figure 3 is an aerial color picture of the property. B. Review of Previous Studies No previous, approved hydrologic / hydraulic studies for the particular watershed were identified. As an initial assessment of the hydrologic and hydraulic behavior of the site, the area was checked with respect to the Puerto Rico Planning Board (PRPB) flood zone maps. Upon review with PRPB, the site is not within flood zone AE as identified in FEMAs Flood Insurance Rate Map 72000C1290H. The most adjacent flood area marks a flood elevation of 2.2-m just south/southeast of the property (lowland area). Please refer to Figure 4 for the project location within the FEMA flood map of the area.
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IV. Applied Methodology and Hydrologic Study Once the problem definition is properly established, the data collection and analysis process was performed. The data collection consisted of the gathering all the applicable hydrologic features of the area by means of field visits, and the revision of available government sources that provided with some of this information. On the other hand, the analysis process involves the mathematical representation of the hydrologic phenomena of the watershed area in order to determine an estimated runoff flow through a known point given a determined rainfall event. From several alternative models, HydroCad was selected as the main simulation engine for this project. It requires the management of sub-models that describe particular processes of the hydrologic cycle. Some of the latter are precipitation (rainfall), interception, infiltration, and unit hydrograph development. A. Rainfall Data The main source for a flood-runoff simulation is the applied rainfall data. The specified rainfall event will ultimately govern the expected runoff flow given constant watershed properties. To obtain a precipitation hyetograph, the accumulated rainfall was estimated at the mass centroid of the watershed area. The National Weather Service Hydrometereological Report Number 42 (or Technical Paper No. 42), was used to determine the accumulated rainfall for the subject storm events. Table 1 describes the accumulated rainfall for all rainfall intensities and durations. Table 1.0 Rainfall-Frequency Data for Naguabo, Puerto Rico (US Weather Bureau, 1961)
Rainfall Intensity (inches) Frequency (years) 1 2 5 10 25 50 100
Intensity (hours) 0.5 1.75 2.00 2.60 3.10 3.50 4.00 4.50 1 2.10 2.50 3.30 3.80 4.50 5.00 5.60 2 2.50 3.00 4.10 5.00 5.50 6.50 7.25 3 2.75 3.50 4.50 5.50 6.50 7.25 8.20 6 3.00 4.00 5.60 6.75 8.00 9.20 10.50
12 3.50 5.00 7.00 8.40 9.50 11.20 13.00 24 4.25 5.75 8.00 10.00 11.50 13.50 15.00
To perform a temporal distribution of this rainfall, the SCS Type II Puerto Rico rainfall distribution was used. This distribution provides with the typical storm precipitation patterns for the area of Puerto Rico.
Detention Pond Study, Club Portofino Project, Santiago y Lima Ward, Naguabo, Puerto Rico
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B. Watershed Limits Definition The watershed considered in this study is defined by the projects property line. The latter will account with natural (ridges) and man-made features (fences and perimeter roads) that will inhibit external flows. The exception will be the two (2) unnamed creeks that cross the property. As envisioned, the projects storm sewer system will connect to a number of detention ponds to be located towards the exiting reaches of these creeks (south/southeast corner of the property). No other storm sewer connection from the project is anticipated at upstream locations of the ponds outlet structures. Therefore, and with the exception of the subject ponds connections, the hydrologic behavior of the creeks watershed areas will not be impacted by the project. Furthermore, a regional analysis of these watershed areas is not necessary since both creeks basically discharge to the Lima Bay immediately after crossing the project. Given the above, the watershed for this study represents the property by itself, which consists of a tract of land of approximately 78.71-acres. C. Bodies of Water Identification As aforementioned throughout this report, there are two (2) unnamed creeks that by pass the subject project. D. Topographic Maps The Naguabo Topographic Quadrangle Map was used to address the terrain and water bodies features for this project. Other sources consisted of maritime zone delimitation plans submitted by Eng. Federico Togni. The subject watershed accounts with sloping patterns that average 13.5 percent in inclination. Maximum elevations were noted at ridge that bisects the property along its center (56-m) while the lower corresponds to the southern and southeastern borders of the parcel (1-m). E. Land Use and Vegetation Cover As described in our Preliminary Evaluation, the site currently corresponds to a vacant tract of land. It is mostly covered by brush, pasture and grass. The proposed conditions land use considered the application of a paved parking and roofs to about 25.7-acres of the total 78.71-acrea of the property. Please refer to Table 2 for a tabulated description of this feature. F. Interception and Infiltration Land surface interception, depression storage and infiltration are referred to in a hydrologic analysis as precipitation losses. These represent the fallen rainfall that does not participate in the
Detention Pond Study, Club Portofino Project, Santiago y Lima Ward, Naguabo, Puerto Rico
Caribbean Hydrologic Engineers 8
runoff process. They are in function of the water storage in trees, brushes, grass, local depressions, cracks, and the infiltration of water to areas beneath the surface, among others. Since the Soil Conservation Service (SCS) interception / infiltration model was used to simulate these hydrologic features within the in-question watershed areas, the Curve Number (CN) of a given sub-basin was determined. To determine the CN, various cover, soil type properties, and the antecedent moisture conditions of the watershed must be effectively determined. The latter were achieved from the revision of the SCS data from Geographical Information Systems, and from our field visits which determine current land use and cover. From the Soil Survey of Naguabo Area Puerto Rico (NRCS, 1979), it arises that the project site accounts with a hydrologic group rating of D (lowest infiltration). Please refer to Table 2 for a quantitative description of these parameters. G. Unit Hydrograph Unit hydrographs are used within the HydroCad sub-basin components to transform the rainfall excess into surface runoff. This hydrograph is synthetically computed from user supplied parameters. HydroCad requires the input of just one subbasin parameter to develop the SCS Dimensionless Unit Hydrograph. This parameter is the Time of Concentration (Tc), which can be subsequently defined as the time required for the outermost fallen raindrop of the sub-basin to hydraulically travel to its exit point. To determine this parameter, the geometric properties of the sub-basin and channels that are related to the flow characteristics of each hydraulic stage must be known. Of several methodologies, the Curve Number Method was selected for the determination of these watersheds Tc. The method is designed for areas of 2,000 acres or less, and is defined by the following variables:
Tc = T lag / 0.6 ,
T lag = [ l 0.8 (S+1) 0.7 ] / 1,900 Y 0.5 ,
S = (1,000 / CN) - 10
where:
Tc = Time of Concentration [hours] T lag =Lag time [hours]
l = Hydraulic length of the watershed [feet] Y = Average land slope [percent]
S = Potential maximum retention [inches] CN = Weighted Curve Number
Detention Pond Study, Club Portofino Project, Santiago y Lima Ward, Naguabo, Puerto Rico
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Note the use of the average land slope, and not the slope of the hydraulic path. Although some care is required to determine this value, the Curve Number method has the advantage of using a small number of fairly objective parameters. This provides more consistent results than some other approaches. The average land slope (or watershed slope) is the slope over an entire land area, rather than the typical slope along the hydraulic path. A theoretical determination of the average land slope requires placing a grid over the area and averaging the slopes for all the squares. The following equation provides a more practical alternative:
Y = C I / A where:
Y = Average land slope (rise/run)
C = Total length of all contour lines I = Contour line interval
A = Total land area
For the post-development scenario, the Time of Concentration needs to be determined within the projects own watershed. To consider sheet, shallow and channel (pipe) flows within these zones, the SCS methodology included in the Technical Release No. 55 (TR-55 software) was used. The following equations describe each stage of flow:
Sheet Flow: Tsf = (0.007 (nL) 0.8) / (P 0.5s 0.4)
Shallow Concentrated Flow: Tsc = L / (3600 V)
Channel Flow: Tch = L / (3600 V)
then, Tc = Tsf + Tsc + Tch where, n = Mannings Roughness Coefficient L = flow length P = 2-year, 24-hour rainfall s = land slope V = average velocity Please refer to Table 2, for a quantitative description of these parameters. H. Summary of Hydrologic Data The following tables summarize the applied hydrological data that was used to simulate the existing and proposed conditions of this project.
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Table 2.0 Existing Conditions Simulation: Physiographic Information Summary Sub-Basin ID Area
(acres) Land Use SCS Soil
Series Weighted
CN Tc
(minutes) Club
Portofino 78.71 Pastures/Grassland/Range
(Fair Cover) D 80 15.9
For the proposed conditions, the physiographic information of the Club Portofino basin was adjusted to reflect the change in land use to be provided by the new ground cover. The modifications were based on the proposed residential districts land use, which in turn influenced the Curve Number designation. Similarly, the time of concentration (Tc) was adjusted to reflect the new drainage ways to be produced by the proposed surface and storm sewer system. Please refer to Table 3 for a description of the adjusted physiographic parameters for the proposed conditions. Table 3.0 Proposed Conditions Simulation: Physiographic Information Summary Sub-Basin ID Area
(acres) Land Use SCS Soil
Series Weighted
CN Tc
(minutes) 25.7 Paved Parking and Roofs Club
Portofino 53.01 Woods and Grass Combination D 85 6.3
I. Initial Hydrologic Results As aforementioned, the described hydrologic data and methodology were incorporated in HydroCad interface software. For the subject purposes, two (2) set of results were computed. The first simulates the existing conditions of the subject basin while the second does the same for the pos-development conditions. Table 4.0 Hydrologic Results Summary: Existing Conditions
Runoff (cfs) Frequency (years) 1 2 5 10 25 50 100
Intensity (hours) 0.5 110 150 259 360 447 560 677 1 140 204 349 447 591 697 827 2 174 252 440 604 698 889 1035 3 193 304 465 635 808 939 1107 6 192 323 547 713 896 1072 1263
12 205 366 591 751 877 1071 1275 24 203 318 495 652 769 926 1042
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Table 5.0 Hydrologic Results Summary: Proposed Conditions
Runoff (cfs) Frequency (years) 1 2 5 10 25 50 100
Intensity (hours) 0.5 337 443 721 969 1175 1439 1707 1 421 581 924 1147 1466 1697 1976 2 487 664 1072 1415 1608 1994 2284 3 512 754 1089 1429 1771 2028 2352 6 459 709 1120 1417 1739 2049 2379
12 392 643 979 1214 1397 1679 1976 24 292 430 635 817 952 1131 1265
Please note the increase in runoff between existing and proposed conditions, produced by the change in land use for the Club Portofino basin for the subject rainfall event frequencies. J. Detention Pond Theory HydroCAD allows the routing of any hydrograph through a detention pond or reservoir. It requires the set up of the Stage / Storage / Discharge characteristics for a particular pond system. Therefore, for every depth or stage in a pond, there is a corresponding storage and discharge which is based on the properties of the outlet structure and the geometry of the pond. HydroCAD allows specifying up to four (4) unique culvert / orifice structures, four (4) unique weir structures, and exfiltration component and a single tailwater elevation. Each structure can be used as an independent outflow or as part of a multi-stage system. In computing the outflows, HydroCAD treats the operation of these outlet structures as a function of stage or water surface elevation. Partial and full flow conditions are also computed for inlet and outlet control. The equation used for culvert/orifice structures is:
Q = Co A (2 g hi k) 0.5 (Nb)
where, Q = discharge in cfs A = culvert area (ft 2 ) hi = distance between the water surface and the centroid of the culvert barrel(1/2 flow depth during partial flow) in feet (Under Inlet Control); Distance between the upstream and downstream water surface (Under Outlet Control) Nb = number of barrels Co = orifice coefficient k = 1 (Under Inlet Control);
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1.5 + [(29 n2 L) / R1.33] (Under Outlet Control) The basic equation used to calculate weir flow is:
Q = Cw L H 1.5
where, Q = discharge in cfs Cw = weir coefficient L = length of the weir crest in ft. H = distance between water surface and the crest in ft. The storage volume is computed by considering a trapezoidal basin where:
V = L W D + (L + W) Z D 2 + 4/3 Z 2 D 3 where, V = storage at stage D, ft 3 D = stage or depth in ft. L = bottom length in ft. W = bottom width in ft. Z = side slope, (Z:1) (H:V) HydroCAD uses the Storage Indication Method which uses the stage / storage / discharge relationship, and inflow hydrograph and the following relationship: I - O = ds / dt where, I = inflow O = outflow. ds / dt = change in storage K. Detention Pond Parameters Based on the aforementioned building distribution, we chose the southeast corner of the property as the ideal location for the detention facilities. The approach will be to develop two (2) independent detention ponds, one for each side of the center ridge that bisects the property. This same divide also applies for the east and west unnamed creeks that travel across the parcel. Therefore each pond will discharge to its corresponding creek just prior their exit from the property. Using HydroCad features, the following detention pond geometry and outlet structure were simulated for the presented rainfall frequencies and durations. Please refer to Tables 6.0 and 7.0 for a general description of this system features:
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Table 6.0 Summary of Pond and Outlet Structure Parameters: West Portofino Pond
Parameter Value
Storage Method Width, B
Open Pond 51-m (168-ft)
Length, L 51-m (168-ft) Height, H
Side Slopes, Z : 1 3.75-m (12.3-ft)
2 Material Earth / Grass
Invert Elevation To be Adjusted to Field Conditions Device 1 (Pond Outlet) Section 5-ft. (H). X 8-ft. (W)
Device 1 (Pond Outlet) Number of Barrels 2 Device 1 (Pond Outlet) Invert Elevation Equal to Ponds Invert
Device 1 (Pond Outlet) Maximum Length 15.2-m (50-ft) Device 1 (Pond Outlet) Slope, %. 0.01 Device 1 (Pond Outlet) N-value. 0.013 Device 1 (Pond Outlet) Material
Minimum Barrel Outlet Invert Elevation Reinforced Concrete
As per Shown Outlet Slope Table 7.0 Summary of Pond and Outlet Structure Parameters: East Portofino Pond
Parameter Value
Storage Method Bottom Width, B
Open Pond 57-m (187-ft)
Bottom Length, L 57-m (187-ft) Height, H
Side Slopes, Z : 1 5.25-m (17.3-ft)
2 Material Earth / Grass
Device 1 (Pond Outlet) Section 5-ft. (H). X 7-ft. (W) Device 1 (Pond Outlet) Number of Barrels 1
Device 1 (Pond Outlet) Invert Elevation Equal to Ponds Invert Device 1 (Pond Outlet) Maximum Length 15.2-m (50-ft)
Device 1 (Pond Outlet) Slope, %. 0.01 Device 1 (Pond Outlet) N-value. 0.013 Device 1 (Pond Outlet) Material
Minimum Barrel Outlet Invert Elevation Reinforced Concrete
As per Shown Outlet Slope Device 2 (Low Flow) Diameter 0.20-m (8-in.)
Device 2 (Low Flow) Number of Barrels 1 Device 2 (Low Flow) Invert Elevation 2.4-m (8-ft)
Device 2 (Low Flow) Length 1-ft Device 2 (Low Flow) Material Reinforced Concrete
Device 3 (Grate) Section 4-ft. (H). X 5-ft. (W) Device 3 (Grate) Number of Barrels 2
Device 3 (Grate) Invert Elevation 0.6 (10-ft) Above Ponds Invert Device 3 (Grate) Length 1-ft
Device 3 (Grate) Material Reinforced Concrete
Detention Pond Study, Club Portofino Project, Santiago y Lima Ward, Naguabo, Puerto Rico
Caribbean Hydrologic Engineers 14
Please note that the bottom, width and height dimensions of the pond may be adjusted to accommodate other geometries, as long as the computed storage volume is not altered. In any case, a final revision of this study shall be completed once final grading and site data is available. In addition, the ponds shall be equipped with the corresponding pilot channels that enable flows to travel from storm sewer pipe outlets to the ponds outlet structure. All outlet structure devices shall account with debris racks and grates in order to avoid waste transport downstream of the pond. Furthermore, the pond shall account with vehicle access ramps appropriate for maintenance tasks. All top of pond perimeter shall include the corresponding access control fences and gates (minimum height of 4-ft.). Please refer to the Appendix of this report for the corresponding drawings and outlet structures detail schematics. L. Final Hydrologic Results Table 7 presents the hydrologic results for the existing and proposed with detention pond conditions of the subject project. Table 8.0 Hydrologic Results Summary: Proposed Conditions with Ponds
Runoff (cfs) Frequency (years) 1 2 5 10 25 50 100 Intensity (hours)
0.5 88 121 211 293 364 465 577 1 114 169 286 367 498 602 733 2 144 206 358 509 601 795 937 3 159 248 380 539 713 848 1002 6 158 259 454 621 812 993 1148
12 166 291 514 684 820 1025 1194 24 160 261 447 616 741 902 1019
Please note that the comparison between the pre-development, post-development and post-development with reservoir scenarios runoff indicates that all post development flows with reservoir are less or equal to the pre-development flows. Therefore, the above detention system complies with Puerto Rico Planning Board criterion for new developments. For a full description of all input data and results output and graphs, please refer to the Appendix of this document.
Detention Pond Study, Club Portofino Project, Santiago y Lima Ward, Naguabo, Puerto Rico
Caribbean Hydrologic Engineers 16
VI. References
1. USGS, Topographic Map of the Naguabo Quadrangle, United States Geological Survey, Washington, D.C., 1982.
2. Puerto Rico Planning Board, Rule Number 3, Reglamento de Lotificacin y
Urbanizacin. 2001
3. Federal Emergency Management Administration (FEMA). Flood Insurance Rate Map (FIRM), Naguabo, Puerto Rico.
4. National Resources Conservation Service (NRCS), Technical Release 55 Urban
Hydrology for Small Watershed. 1986.
5. US Army Corps of Engineers, Hydrologic Engineering Center, HEC-HMS Hydrologic Modeling Software, Users Manual. 1997.
6. Intellisolve, HydroCad 8.0, Owners Manual. 2006.
7. U.S. Weather Bureau, Generalized Estimates of Probable Maximum Precipitation and
Rainfall Frequency Data for Puerto Rico and Virgin Islands (Technical Paper No. 42), U.S. Department of Commerce, Washington, D.C., 1961.
8. National Resources Conservation Service (NRCS), Soil Survey of Humacao Area of
Eastern Puerto Rico. 1979.
9. Singh, V. Elementary Hydrology, Prentice Hall, Englewood Cliffs, New Jersey. 1992.
10. Gribbin, J. Introduction to Hydraulics and Hydrology, Delmar, Albany, NY. 1997.
11. Haestad, Durrans. Stormwater Conveyance Modeling and Design, Haestad Press, Waterbury, CT. 2003
12. US Army Corps of Engineers, Hydrologic Engineering Center, HEC-RAS River Analysis
System, Users Manual. 1997.
Detention Pond Study, Club Portofino Project, Santiago y Lima Ward, Naguabo, Puerto Rico
Caribbean Hydrologic Engineers 17
VII. Appendix
Detention Pond Study, Club Portofino Project, Santiago y Lima Ward, Naguabo, Puerto Rico
Caribbean Hydrologic Engineers 1
A. Figures
!"
Detention Pond Study, Club Portofino Project, Santiago y Lima Ward, Naguabo, Puerto Rico
Caribbean Hydrologic Engineers 2
B. Rainfall Distribution: SCS Type II Puerto Rico
// HydroCAD Rainfall table// Copyright (c) 2004 HydroCAD Software Solutions LLC// DO NOT MIDIFY THIS FILE! For details see Rainfall.txt
name=Type II 24-hr Tabulartimeunits=hoursduration=24comment=Type II 24-hour tabular mass curve to match TR-20smoothing=false
depth=.000 .002 .005 .008 .011 .014 .017 .02 .023 .026depth=.029 .032 .035 .038 .041 .044 .048 .052 .056 .060depth=.064 .068 .072 .076 .080 .085 .090 .095 .100 .105depth=.110 .115 .120 .126 .133 .140 .147 .155 .163 .172depth=.181 .191 .203 .218 .236 .257 .283 .387 .663 .707depth=.735 .758 .776 .791 .804 .815 .825 .834 .842 .849depth=.856 .863 .869 .875 .881 .887 .893 .898 .903 .908depth=.913 .918 .922 .926 .930 .934 .938 .942 .946 .950depth=.953 .956 .959 .962 .965 .968 .971 .974 .977 .980depth=.983 .986 .989 .992 .995 .998 1.000
Detention Pond Study, Club Portofino Project, Santiago y Lima Ward, Naguabo, Puerto Rico
Caribbean Hydrologic Engineers 3
C. HydroCad Output: Summary of All Rainfall Frequencies and Durations
1S
Clu
b P
orto
fino
Pro
ject
Pre
Dev
4S
Wes
t Clu
b P
orto
fino
Pro
ject
Pos
t Dev
6S
Eas
t Clu
b P
orto
fino
Pro
ject
Pos
t Dev
7S
Tota
l Clu
b P
orto
fino
Pro
ject
Pos
t Dev
5P
Wes
t Por
tofin
o P
ond
8P
Eas
t Por
tofin
o P
ond
9L
Com
bine
d P
ost D
ev O
utle
t
Dra
inag
e D
iagr
am fo
r Nag
uabo
Pla
ya P
roje
ctP
repa
red
by C
arib
bean
Hyd
rolo
gic
Eng
inee
rs
1
0/18
/200
6H
ydro
CA
D
8.0
0 s
/n 0
0330
9
200
6 H
ydro
CA
D S
oftw
are
Sol
utio
ns L
LC
Sub
cat
Rea
chP
ond
Link
Type
II 2
4-hr
-15
min
.PR
Tab
ular
1.0
0 hr
s N
ag 1
HR
-1yr
Rai
nfal
l=2.
10"
Nag
uabo
Pla
ya P
roje
ctP
age
2P
repa
red
by C
arib
bean
Hyd
rolo
gic
Eng
inee
rs10
/18/
2006
Hyd
roC
AD
8
.00
s/n
003
309
2
006
Hyd
roC
AD
Sof
twar
e S
olut
ions
LLC
Subc
atch
men
t 1S:
Clu
b Po
rtof
ino
Proj
ect P
re D
ev
Run
off
=13
9.84
cfs
@
0.72
hrs
, V
olum
e=4.
095
af,
Dep
th=
0.62
"
Run
off b
y S
CS
TR
-20
met
hod,
UH
=SC
S, T
ime
Spa
n= 0
.00-
24.0
0 hr
s, d
t= 0
.01
hrs
Type
II 2
4-hr
-15
min
.PR
Tab
ular
1.0
0 hr
s N
ag 1
HR
-1yr
Rai
nfal
l=2.
10"
Are
a (a
c)C
ND
escr
iptio
n78
.710
80P
astu
re/g
rass
land
/rang
e, G
ood,
HS
G D
78.7
10P
ervi
ous
Are
a
TcLe
ngth
Slo
peV
eloc
ityC
apac
ityD
escr
iptio
n(m
in)
(feet
)(ft
/ft)
(ft/s
ec)
(cfs
)15
.92,
145
0.13
502.
24La
g/C
N M
etho
d,
Con
tour
Len
gth=
14,
026'
Int
erva
l= 3
3'
Subc
atch
men
t 4S:
Wes
t Clu
b Po
rtof
ino
Proj
ect P
ost D
ev
Run
off
=27
4.39
cfs
@
0.58
hrs
, V
olum
e=3.
716
af,
Dep
th=
0.87
"
Run
off b
y S
CS
TR
-20
met
hod,
UH
=SC
S, T
ime
Spa
n= 0
.00-
24.0
0 hr
s, d
t= 0
.01
hrs
Type
II 2
4-hr
-15
min
.PR
Tab
ular
1.0
0 hr
s N
ag 1
HR
-1yr
Rai
nfal
l=2.
10"
Are
a (a
c)C
ND
escr
iptio
n16
.780
98P
aved
par
king
& ro
ofs
34.5
2079
Woo
ds/g
rass
com
b., G
ood,
HS
G D
51.3
0085
Wei
ghte
d A
vera
ge34
.520
Per
viou
s A
rea
16.7
80Im
perv
ious
Are
a
TcLe
ngth
Slo
peV
eloc
ityC
apac
ityD
escr
iptio
n(m
in)
(feet
)(ft
/ft)
(ft/s
ec)
(cfs
)4.
690
0.13
500.
33Sh
eet F
low
, New
Lan
dsca
peG
rass
: Den
se
n= 0
.240
P
2= 5
.75"
0.1
500.
1350
7.46
Shal
low
Con
cent
rate
d Fl
ow,
Pav
ed
Kv=
20.
3 fp
s1.
62,
089
0.13
5021
.84
38.6
0C
ircul
ar C
hann
el (p
ipe)
, Fro
m C
urb
to O
utle
tD
iam
= 18
.0"
Are
a= 1
.8 s
f P
erim
= 4.
7' r
= 0.
38'
n= 0
.013
Con
cret
e pi
pe, b
ends
& c
onne
ctio
ns6.
32,
229
Tota
l
Subc
atch
men
t 6S:
Eas
t Clu
b Po
rtof
ino
Proj
ect P
ost D
ev
Run
off
=14
6.56
cfs
@
0.58
hrs
, V
olum
e=1.
985
af,
Dep
th=
0.87
"
Run
off b
y S
CS
TR
-20
met
hod,
UH
=SC
S, T
ime
Spa
n= 0
.00-
24.0
0 hr
s, d
t= 0
.01
hrs
Type
II 2
4-hr
-15
min
.PR
Tab
ular
1.0
0 hr
s N
ag 1
HR
-1yr
Rai
nfal
l=2.
10"
Type
II 2
4-hr
-15
min
.PR
Tab
ular
1.0
0 hr
s N
ag 1
HR
-1yr
Rai
nfal
l=2.
10"
Nag
uabo
Pla
ya P
roje
ctP
age
3P
repa
red
by C
arib
bean
Hyd
rolo
gic
Eng
inee
rs10
/18/
2006
Hyd
roC
AD
8
.00
s/n
003
309
2
006
Hyd
roC
AD
Sof
twar
e S
olut
ions
LLC
Are
a (a
c)C
ND
escr
iptio
n8.
960
98P
aved
par
king
& ro
ofs
18.4
4079
Woo
ds/g
rass
com
b., G
ood,
HS
G D
27.4
0085
Wei
ghte
d A
vera
ge18
.440
Per
viou
s A
rea
8.96
0Im
perv
ious
Are
a
TcLe
ngth
Slo
peV
eloc
ityC
apac
ityD
escr
iptio
n(m
in)
(feet
)(ft
/ft)
(ft/s
ec)
(cfs
)4.
690
0.13
500.
33Sh
eet F
low
, New
Lan
dsca
peG
rass
: Den
se
n= 0
.240
P
2= 5
.75"
0.1
500.
1350
7.46
Shal
low
Con
cent
rate
d Fl
ow,
Pav
ed
Kv=
20.
3 fp
s1.
62,
089
0.13
5021
.84
38.6
0C
ircul
ar C
hann
el (p
ipe)
, Fro
m C
urb
to O
utle
tD
iam
= 18
.0"
Are
a= 1
.8 s
f P
erim
= 4.
7' r
= 0.
38'
n= 0
.013
Con
cret
e pi
pe, b
ends
& c
onne
ctio
ns6.
32,
229
Tota
l
Subc
atch
men
t 7S:
Tot
al C
lub
Port
ofin
o Pr
ojec
t Pos
t Dev
Run
off
=42
1.00
cfs
@
0.58
hrs
, V
olum
e=5.
701
af,
Dep
th=
0.87
"
Run
off b
y S
CS
TR
-20
met
hod,
UH
=SC
S, T
ime
Spa
n= 0
.00-
24.0
0 hr
s, d
t= 0
.01
hrs
Type
II 2
4-hr
-15
min
.PR
Tab
ular
1.0
0 hr
s N
ag 1
HR
-1yr
Rai
nfal
l=2.
10"
Are
a (a
c)C
ND
escr
iptio
n25
.700
98P
aved
par
king
& ro
ofs
53.0
1079
Woo
ds/g
rass
com
b., G
ood,
HS
G D
78.7
1085
Wei
ghte
d A
vera
ge53
.010
Per
viou
s A
rea
25.7
00Im
perv
ious
Are
a
TcLe
ngth
Slo
peV
eloc
ityC
apac
ityD
escr
iptio
n(m
in)
(feet
)(ft
/ft)
(ft/s
ec)
(cfs
)4.
690
0.13
500.
33Sh
eet F
low
, New
Lan
dsca
peG
rass
: Den
se
n= 0
.240
P
2= 5
.75"
0.1
500.
1350
7.46
Shal
low
Con
cent
rate
d Fl
ow,
Pav
ed
Kv=
20.
3 fp
s1.
62,
089
0.13
5021
.84
38.6
0C
ircul
ar C
hann
el (p
ipe)
, Fro
m C
urb
to O
utle
tD
iam
= 18
.0"
Are
a= 1
.8 s
f P
erim
= 4.
7' r
= 0.
38'
n= 0
.013
Con
cret
e pi
pe, b
ends
& c
onne
ctio
ns6.
32,
229
Tota
l
Pond
5P:
Wes
t Por
tofin
o Po
nd
Inflo
w A
rea
=51
.300
ac,
Inf
low
Dep
th =
0.
87"
for
Nag
1H
R-1
yr e
vent
Inflo
w=
274.
39 c
fs @
0.
58 h
rs,
Vol
ume=
3.71
6 af
Out
flow
=11
3.25
cfs
@
0.66
hrs
, V
olum
e=3.
716
af,
Atte
n= 5
9%,
Lag=
5.0
min
Prim
ary
=11
3.25
cfs
@
0.66
hrs
, V
olum
e=3.
716
af
Rou
ting
by S
tor-
Ind
met
hod,
Tim
e S
pan=
0.0
0-24
.00
hrs,
dt=
0.0
1 hr
s
Type
II 2
4-hr
-15
min
.PR
Tab
ular
1.0
0 hr
s N
ag 1
HR
-1yr
Rai
nfal
l=2.
10"
Nag
uabo
Pla
ya P
roje
ctP
age
4P
repa
red
by C
arib
bean
Hyd
rolo
gic
Eng
inee
rs10
/18/
2006
Hyd
roC
AD
8
.00
s/n
003
309
2
006
Hyd
roC
AD
Sof
twar
e S
olut
ions
LLC
Pea
k E
lev=
9.6
9' @
0.6
6 hr
s S
urf.A
rea=
0.9
69 a
c S
tora
ge=
1.58
6 af
Plu
g-Fl
ow d
eten
tion
time=
14.
1 m
in c
alcu
late
d fo
r 3.7
14 a
f (10
0% o
f inf
low
)C
ente
r-of
-Mas
s de
t. tim
e= 1
4.2
min
( 54
.9 -
40.7
)
Vol
ume
Inve
rtA
vail.
Sto
rage
Sto
rage
Des
crip
tion
#18.
00'
9.12
4 af
150.
00'W
x 2
62.4
0'L
x 8.
50'H
46m
X80m
X2.5
9m Z
=2.0
Dev
ice
Rou
ting
Inve
rtO
utle
t Dev
ices
#1P
rimar
y8.
00'
8.00
' W x
5.0
0' H
x 5
0.0'
long
Cul
vert
X 2
.00
R
CP
, squ
are
edge
hea
dwal
l, K
e= 0
.500
O
utle
t Inv
ert=
7.5
0'
S=
0.01
00 '/
' C
c= 0
.900
n=
0.0
13 C
oncr
ete
pipe
, ben
ds &
con
nect
ions
Prim
ary
Out
Flow
Max
=113
.10
cfs
@ 0
.66
hrs
HW
=9.6
9'
(Fre
e D
isch
arge
)1=
Cul
vert
(Inl
et C
ontro
ls 1
13.1
0 cf
s @
4.1
8 fp
s)
Pond
8P:
Eas
t Por
tofin
o Po
nd
Inflo
w A
rea
=27
.400
ac,
Inf
low
Dep
th =
0.
87"
for
Nag
1H
R-1
yr e
vent
Inflo
w=
146.
56 c
fs @
0.
58 h
rs,
Vol
ume=
1.98
5 af
Out
flow
=1.
56 c
fs @
1.
15 h
rs,
Vol
ume=
1.55
3 af
, A
tten=
99%
, La
g= 3
3.9
min
Prim
ary
=1.
56 c
fs @
1.
15 h
rs,
Vol
ume=
1.55
3 af
Rou
ting
by S
tor-
Ind
met
hod,
Tim
e S
pan=
0.0
0-24
.00
hrs,
dt=
0.0
1 hr
sP
eak
Ele
v= 9
.19'
@ 1
.15
hrs
Sur
f.Are
a= 1
.639
ac
Sto
rage
= 1.
916
af
Plu
g-Fl
ow d
eten
tion
time=
494
.3 m
in c
alcu
late
d fo
r 1.5
53 a
f (78
% o
f inf
low
)C
ente
r-of
-Mas
s de
t. tim
e= 4
90.4
min
( 53
1.1
- 40.
7 )
Vol
ume
Inve
rtA
vail.
Sto
rage
Sto
rage
Des
crip
tion
#18.
00'
15.2
52 a
f26
2.40
'W x
262
.40'
L x
8.50
'H 8
0mX8
0mX2
.59m
Z=2
.0
Dev
ice
Rou
ting
Inve
rtO
utle
t Dev
ices
#1P
rimar
y8.
00'
7.00
' W x
5.0
0' H
x 5
0.0'
long
Cul
vert
R
CP
, squ
are
edge
hea
dwal
l, K
e= 0
.500
O
utle
t Inv
ert=
7.5
0'
S=
0.01
00 '/
' C
c= 0
.900
n=
0.0
13 C
oncr
ete
pipe
, ben
ds &
con
nect
ions
#2
Dev
ice
18.
00'
8.0"
Ver
t. O
rific
e/G
rate
C=
0.60
0
#3D
evic
e 1
10.0
0'5.
00' W
x 4
.00'
H V
ert.
Orif
ice/
Gra
te X
2.0
0 C
= 0.
600
Prim
ary
Out
Flow
Max
=1.5
6 cf
s @
1.1
5 hr
s H
W=9
.19'
(F
ree
Dis
char
ge)
1=C
ulve
rt (P
asse
s 1.
56 c
fs o
f 29.
19 c
fs p
oten
tial f
low
)2=
Orif
ice/
Gra
te (
Orif
ice
Con
trols
1.5
6 cf
s @
4.4
6 fp
s)3=
Orif
ice/
Gra
te (
Con
trols
0.0
0 cf
s)
Type
II 2
4-hr
-15
min
.PR
Tab
ular
1.0
0 hr
s N
ag 1
HR
-1yr
Rai
nfal
l=2.
10"
Nag
uabo
Pla
ya P
roje
ctP
age
5P
repa
red
by C
arib
bean
Hyd
rolo
gic
Eng
inee
rs10
/18/
2006
Hyd
roC
AD
8
.00
s/n
003
309
2
006
Hyd
roC
AD
Sof
twar
e S
olut
ions
LLC
Link
9L:
Com
bine
d Po
st D
ev O
utle
t
Inflo
w A
rea
=78
.700
ac,
Inf
low
Dep
th >
0.
80"
for
Nag
1H
R-1
yr e
vent
Inflo
w=
114.
36 c
fs @
0.
66 h
rs,
Vol
ume=
5.26
9 af
Prim
ary
=11
4.36
cfs
@
0.66
hrs
, V
olum
e=5.
269
af,
Atte
n= 0
%,
Lag=
0.0
min
Prim
ary
outfl
ow =
Inflo
w, T
ime
Spa
n= 0
.00-
24.0
0 hr
s, d
t= 0
.01
hrs
Type
II 2
4-hr
-15
min
.PR
Tab
ular
1.0
0 hr
s N
ag 1
HR
-25y
r R
ainf
all=
4.50
"N
agua
bo P
laya
Pro
jec
Pag
e 6
Pre
pare
d by
Car
ibbe
an H
ydro
logi
c E
ngin
eers
10/1
8/20
06H
ydro
CA
D
8.0
0 s
/n 0
0330
9
200
6 H
ydro
CA
D S
oftw
are
Sol
utio
ns L
LC
Subc
atch
men
t 1S:
Clu
b Po
rtof
ino
Proj
ect P
re D
ev
Run
off
=59
0.65
cfs
@
0.71
hrs
, V
olum
e=16
.146
af,
Dep
th=
2.46
"
Run
off b
y S
CS
TR
-20
met
hod,
UH
=SC
S, T
ime
Spa
n= 0
.00-
24.0
0 hr
s, d
t= 0
.01
hrs
Type
II 2
4-hr
-15
min
.PR
Tab
ular
1.0
0 hr
s N
ag 1
HR
-25y
r R
ainf
all=
4.50
"
Are
a (a
c)C
ND
escr
iptio
n78
.710
80P
astu
re/g
rass
land
/rang
e, G
ood,
HS
G D
78.7
10P
ervi
ous
Are
a
TcLe
ngth
Slo
peV
eloc
ityC
apac
ityD
escr
iptio
n(m
in)
(feet
)(ft
/ft)
(ft/s
ec)
(cfs
)15
.92,
145
0.13
502.
24La
g/C
N M
etho
d,
Con
tour
Len
gth=
14,
026'
Int
erva
l= 3
3'
Subc
atch
men
t 4S:
Wes
t Clu
b Po
rtof
ino
Proj
ect P
ost D
ev
Run
off
=95
5.58
cfs
@
0.58
hrs
, V
olum
e=12
.437
af,
Dep
th=
2.91
"
Run
off b
y S
CS
TR
-20
met
hod,
UH
=SC
S, T
ime
Spa
n= 0
.00-
24.0
0 hr
s, d
t= 0
.01
hrs
Type
II 2
4-hr
-15
min
.PR
Tab
ular
1.0
0 hr
s N
ag 1
HR
-25y
r R
ainf
all=
4.50
"
Are
a (a
c)C
ND
escr
iptio
n16
.780
98P
aved
par
king
& ro
ofs
34.5
2079
Woo
ds/g
rass
com
b., G
ood,
HS
G D
51.3
0085
Wei
ghte
d A
vera
ge34
.520
Per
viou
s A
rea
16.7
80Im
perv
ious
Are
a
TcLe
ngth
Slo
peV
eloc
ityC
apac
ityD
escr
iptio
n(m
in)
(feet
)(ft
/ft)
(ft/s
ec)
(cfs
)4.
690
0.13
500.
33Sh
eet F
low
, New
Lan
dsca
peG
rass
: Den
se
n= 0
.240
P
2= 5
.75"
0.1
500.
1350
7.46
Shal
low
Con
cent
rate
d Fl
ow,
Pav
ed
Kv=
20.
3 fp
s1.
62,
089
0.13
5021
.84
38.6
0C
ircul
ar C
hann
el (p
ipe)
, Fro
m C
urb
to O
utle
tD
iam
= 18
.0"
Are
a= 1
.8 s
f P
erim
= 4.
7' r
= 0.
38'
n= 0
.013
Con
cret
e pi
pe, b
ends
& c
onne
ctio
ns6.
32,
229
Tota
l
Subc
atch
men
t 6S:
Eas
t Clu
b Po
rtof
ino
Proj
ect P
ost D
ev
Run
off
=51
0.39
cfs
@
0.58
hrs
, V
olum
e=6.
643
af,
Dep
th=
2.91
"
Run
off b
y S
CS
TR
-20
met
hod,
UH
=SC
S, T
ime
Spa
n= 0
.00-
24.0
0 hr
s, d
t= 0
.01
hrs
Type
II 2
4-hr
-15
min
.PR
Tab
ular
1.0
0 hr
s N
ag 1
HR
-25y
r R
ainf
all=
4.50
"
Type
II 2
4-hr
-15
min
.PR
Tab
ular
1.0
0 hr
s N
ag 1
HR
-25y
r R
ainf
all=
4.50
"N
agua
bo P
laya
Pro
jec
Pag
e 7
Pre
pare
d by
Car
ibbe
an H
ydro
logi
c E
ngin
eers
10/1
8/20
06H
ydro
CA
D
8.0
0 s
/n 0
0330
9
200
6 H
ydro
CA
D S
oftw
are
Sol
utio
ns L
LC
Are
a (a
c)C
ND
escr
iptio
n8.
960
98P
aved
par
king
& ro
ofs
18.4
4079
Woo
ds/g
rass
com
b., G
ood,
HS
G D
27.4
0085
Wei
ghte
d A
vera
ge18
.440
Per
viou
s A
rea
8.96
0Im
perv
ious
Are
a
TcLe
ngth
Slo
peV
eloc
ityC
apac
ityD
escr
iptio
n(m
in)
(feet
)(ft
/ft)
(ft/s
ec)
(cfs
)4.
690
0.13
500.
33Sh
eet F
low
, New
Lan
dsca
peG
rass
: Den
se
n= 0
.240
P
2= 5
.75"
0.1
500.
1350
7.46
Shal
low
Con
cent
rate
d Fl
ow,
Pav
ed
Kv=
20.
3 fp
s1.
62,
089
0.13
5021
.84
38.6
0C
ircul
ar C
hann
el (p
ipe)
, Fro
m C
urb
to O
utle
tD
iam
= 18
.0"
Are
a= 1
.8 s
f P
erim
= 4.
7' r
= 0.
38'
n= 0
.013
Con
cret
e pi
pe, b
ends
& c
onne
ctio
ns6.
32,
229
Tota
l
Subc
atch
men
t 7S:
Tot
al C
lub
Port
ofin
o Pr
ojec
t Pos
t Dev
Run
off
=1,
466.
16 c
fs @
0.
58 h
rs,
Vol
ume=
19.0
81 a
f, D
epth
=2.
91"
Run
off b
y S
CS
TR
-20
met
hod,
UH
=SC
S, T
ime
Spa
n= 0
.00-
24.0
0 hr
s, d
t= 0
.01
hrs
Type
II 2
4-hr
-15
min
.PR
Tab
ular
1.0
0 hr
s N
ag 1
HR
-25y
r R
ainf
all=
4.50
"
Are
a (a
c)C
ND
escr
iptio
n25
.700
98P
aved
par
king
& ro
ofs
53.0
1079
Woo
ds/g
rass
com
b., G
ood,
HS
G D
78.7
1085
Wei
ghte
d A
vera
ge53
.010
Per
viou
s A
rea
25.7
00Im
perv
ious
Are
a
TcLe
ngth
Slo
peV
eloc
ityC
apac
ityD
escr
iptio
n(m
in)
(feet
)(ft
/ft)
(ft/s
ec)
(cfs
)4.
690
0.13
500.
33Sh
eet F
low
, New
Lan
dsca
peG
rass
: Den
se
n= 0
.240
P
2= 5
.75"
0.1
500.
1350
7.46
Shal
low
Con
cent
rate
d Fl
ow,
Pav
ed
Kv=
20.
3 fp
s1.
62,
089
0.13
5021
.84
38.6
0C
ircul
ar C
hann
el (p
ipe)
, Fro
m C
urb
to O
utle
tD
iam
= 18
.0"
Are
a= 1
.8 s
f P
erim
= 4.
7' r
= 0.
38'
n= 0
.013
Con
cret
e pi
pe, b
ends
& c
onne
ctio
ns6.
32,
229
Tota
l
Pond
5P:
Wes
t Por
tofin
o Po
nd
Inflo
w A
rea
=51
.300
ac,
Inf
low
Dep
th =
2.
91"
for
Nag
1H
R-2
5yr e
vent
Inflo
w=
955.
58 c
fs @
0.
58 h
rs,
Vol
ume=
12.4
37 a
fO
utflo
w=
483.
80 c
fs @
0.
64 h
rs,
Vol
ume=
12.4
37 a
f, A
tten=
49%
, La
g= 3
.7 m
inP
rimar
y=
483.
80 c
fs @
0.
64 h
rs,
Vol
ume=
12.4
37 a
f
Rou
ting
by S
tor-
Ind
met
hod,
Tim
e S
pan=
0.0
0-24
.00
hrs,
dt=
0.0
1 hr
s
Type
II 2
4-hr
-15
min
.PR
Tab
ular
1.0
0 hr
s N
ag 1
HR
-25y
r R
ainf
all=
4.50
"N
agua
bo P
laya
Pro
jec
Pag
e 8
Pre
pare
d by
Car
ibbe
an H
ydro
logi
c E
ngin
eers
10/1
8/20
06H
ydro
CA
D
8.0
0 s
/n 0
0330
9
200
6 H
ydro
CA
D S
oftw
are
Sol
utio
ns L
LC
Pea
k E
lev=
12.
86' @
0.6
4 hr
s S
urf.A
rea=
1.0
96 a
c S
tora
ge=
4.85
2 af
Plu
g-Fl
ow d
eten
tion
time=
9.7
min
cal
cula
ted
for 1
2.43
7 af
(100
% o
f inf
low
)C
ente
r-of
-Mas
s de
t. tim
e= 9
.5 m
in (
48.8
- 39
.3 )
Vol
ume
Inve
rtA
vail.
Sto
rage
Sto
rage
Des
crip
tion
#18.
00'
9.12
4 af
150.
00'W
x 2
62.4
0'L
x 8.
50'H
46m
X80m
X2.5
9m Z
=2.0
Dev
ice
Rou
ting
Inve
rtO
utle
t Dev
ices
#1P
rimar
y8.
00'
8.00
' W x
5.0
0' H
x 5
0.0'
long
Cul
vert
X 2
.00
R
CP
, squ
are
edge
hea
dwal
l, K
e= 0
.500
O
utle
t Inv
ert=
7.5
0'
S=
0.01
00 '/
' C
c= 0
.900
n=
0.0
13 C
oncr
ete
pipe
, ben
ds &
con
nect
ions
Prim
ary
Out
Flow
Max
=483
.48
cfs
@ 0
.64
hrs
HW
=12.
86'
(Fre
e D
isch
arge
)1=
Cul
vert
(Bar
rel C
ontro
ls 4
83.4
8 cf
s @
8.2
9 fp
s)
Pond
8P:
Eas
t Por
tofin
o Po
nd
Inflo
w A
rea
=27
.400
ac,
Inf
low
Dep
th =
2.
91"
for
Nag
1H
R-2
5yr e
vent
Inflo
w=
510.
39 c
fs @
0.
58 h
rs,
Vol
ume=
6.64
3 af
Out
flow
=43
.90
cfs
@
0.88
hrs
, V
olum
e=5.
822
af,
Atte
n= 9
1%,
Lag=
18.
1 m
inP
rimar
y=
43.9
0 cf
s @
0.
88 h
rs,
Vol
ume=
5.82
2 af
Rou
ting
by S
tor-
Ind
met
hod,
Tim
e S
pan=
0.0
0-24
.00
hrs,
dt=
0.0
1 hr
sP
eak
Ele
v= 1
1.18
' @ 0
.88
hrs
Sur
f.Are
a= 1
.738
ac
Sto
rage
= 5.
271
af
Plu
g-Fl
ow d
eten
tion
time=
315
.0 m
in c
alcu
late
d fo
r 5.8
22 a
f (88
% o
f inf
low
)C
ente
r-of
-Mas
s de
t. tim
e= 3
12.5
min
( 35
1.8
- 39.
3 )
Vol
ume
Inve
rtA
vail.
Sto
rage
Sto
rage
Des
crip
tion
#18.
00'
15.2
52 a
f26
2.40
'W x
262
.40'
L x
8.50
'H 8
0mX8
0mX2
.59m
Z=2
.0
Dev
ice
Rou
ting
Inve
rtO
utle
t Dev
ices
#1P
rimar
y8.
00'
7.00
' W x
5.0
0' H
x 5
0.0'
long
Cul
vert
R
CP
, squ
are
edge
hea
dwal
l, K
e= 0
.500
O
utle
t Inv
ert=
7.5
0'
S=
0.01
00 '/
' C
c= 0
.900
n=
0.0
13 C
oncr
ete
pipe
, ben
ds &
con
nect
ions
#2
Dev
ice
18.
00'
8.0"
Ver
t. O
rific
e/G
rate
C=
0.60
0
#3D
evic
e 1
10.0
0'5.
00' W
x 4
.00'
H V
ert.
Orif
ice/
Gra
te X
2.0
0 C
= 0.
600
Prim
ary
Out
Flow
Max
=43.
88 c
fs @
0.8
8 hr
s H
W=1
1.18
' (F
ree
Dis
char
ge)
1=C
ulve
rt (P
asse
s 43
.88
cfs
of 1
18.4
1 cf
s po
tent
ial f
low
)2=
Orif
ice/
Gra
te (
Orif
ice
Con
trols
2.8
3 cf
s @
8.1
2 fp
s)3=
Orif
ice/
Gra
te (
Orif
ice
Con
trols
41.
04 c
fs @
3.4
8 fp
s)
Type
II 2
4-hr
-15
min
.PR
Tab
ular
1.0
0 hr
s N
ag 1
HR
-25y
r R
ainf
all=
4.50
"N
agua
bo P
laya
Pro
jec
Pag
e 9
Pre
pare
d by
Car
ibbe
an H
ydro
logi
c E
ngin
eers
10/1
8/20
06H
ydro
CA
D
8.0
0 s
/n 0
0330
9
200
6 H
ydro
CA
D S
oftw
are
Sol
utio
ns L
LC
Link
9L:
Com
bine
d Po
st D
ev O
utle
t
Inflo
w A
rea
=78
.700
ac,
Inf
low
Dep
th >
2.
78"
for
Nag
1H
R-2
5yr e
vent
Inflo
w=
498.
33 c
fs @
0.
64 h
rs,
Vol
ume=
18.2
59 a
fP
rimar
y=
498.
33 c
fs @
0.
64 h
rs,
Vol
ume=
18.2
59 a
f, A
tten=
0%
, La
g= 0
.0 m
in
Prim
ary
outfl
ow =
Inflo
w, T
ime
Spa
n= 0
.00-
24.0
0 hr
s, d
t= 0
.01
hrs
Type
II 2
4-hr
-15
min
.PR
Tab
ular
1.0
0 hr
s N
ag 1
HR
-2yr
Rai
nfal
l=2.
50"
Nag
uabo
Pla
ya P
roje
ctP
age
10P
repa
red
by C
arib
bean
Hyd
rolo
gic
Eng
inee
rs10
/18/
2006
Hyd
roC
AD
8
.00
s/n
003
309
2
006
Hyd
roC
AD
Sof
twar
e S
olut
ions
LLC
Subc
atch
men
t 1S:
Clu
b Po
rtof
ino
Proj
ect P
re D
ev
Run
off
=20
3.95
cfs
@
0.72
hrs
, V
olum
e=5.
830
af,
Dep
th=
0.89
"
Run
off b
y S
CS
TR
-20
met
hod,
UH
=SC
S, T
ime
Spa
n= 0
.00-
24.0
0 hr
s, d
t= 0
.01
hrs
Type
II 2
4-hr
-15
min
.PR
Tab
ular
1.0
0 hr
s N
ag 1
HR
-2yr
Rai
nfal
l=2.
50"
Are
a (a
c)C
ND
escr
iptio
n78
.710
80P
astu
re/g
rass
land
/rang
e, G
ood,
HS
G D
78.7
10P
ervi
ous
Are
a
TcLe
ngth
Slo
peV
eloc
ityC
apac
ityD
escr
iptio
n(m
in)
(feet
)(ft
/ft)
(ft/s
ec)
(cfs
)15
.92,
145
0.13
502.
24La
g/C
N M
etho
d,
Con
tour
Len
gth=
14,
026'
Int
erva
l= 3
3'
Subc
atch
men
t 4S:
Wes
t Clu
b Po
rtof
ino
Proj
ect P
ost D
ev
Run
off
=37
8.86
cfs
@
0.58
hrs
, V
olum
e=5.
038
af,
Dep
th=
1.18
"
Run
off b
y S
CS
TR
-20
met
hod,
UH
=SC
S, T
ime
Spa
n= 0
.00-
24.0
0 hr
s, d
t= 0
.01
hrs
Type
II 2
4-hr
-15
min
.PR
Tab
ular
1.0
0 hr
s N
ag 1
HR
-2yr
Rai
nfal
l=2.
50"
Are
a (a
c)C
ND
escr
iptio
n16
.780
98P
aved
par
king
& ro
ofs
34.5
2079
Woo
ds/g
rass
com
b., G
ood,
HS
G D
51.3
0085
Wei
ghte
d A
vera
ge34
.520
Per
viou
s A
rea
16.7
80Im
perv
ious
Are
a
TcLe
ngth
Slo
peV
eloc
ityC
apac
ityD
escr
iptio
n(m
in)
(feet
)(ft
/ft)
(ft/s
ec)
(cfs
)4.
690
0.13
500.
33Sh
eet F
low
, New
Lan
dsca
peG
rass
: Den
se
n= 0
.240
P
2= 5
.75"
0.1
500.
1350
7.46
Shal
low
Con
cent
rate
d Fl
ow,
Pav
ed
Kv=
20.
3 fp
s1.
62,
089
0.13
5021
.84
38.6
0C
ircul
ar C
hann
el (p
ipe)
, Fro
m C
urb
to O
utle
tD
iam
= 18
.0"
Are
a= 1
.8 s
f P
erim
= 4.
7' r
= 0.
38'
n= 0
.013
Con
cret
e pi
pe, b
ends
& c
onne
ctio
ns6.
32,
229
Tota
l
Subc
atch
men
t 6S:
Eas
t Clu
b Po
rtof
ino
Proj
ect P
ost D
ev
Run
off
=20
2.35
cfs
@
0.58
hrs
, V
olum
e=2.
691
af,
Dep
th=
1.18
"
Run
off b
y S
CS
TR
-20
met
hod,
UH
=SC
S, T
ime
Spa
n= 0
.00-
24.0
0 hr
s, d
t= 0
.01
hrs
Type
II 2
4-hr
-15
min
.PR
Tab
ular
1.0
0 hr
s N
ag 1
HR
-2yr
Rai
nfal
l=2.
50"
Type
II 2
4-hr
-15
min
.PR
Tab
ular
1.0
0 hr
s N
ag 1
HR
-2yr
Rai
nfal
l=2.
50"
Nag
uabo
Pla
ya P
roje
ctP
age
11P
repa
red
by C
arib
bean
Hyd
rolo
gic
Eng
inee
rs10
/18/
2006
Hyd
roC
AD
8
.00
s/n
003
309
2
006
Hyd
roC
AD
Sof
twar
e S
olut
ions
LLC
Are
a (a
c)C
ND
escr
iptio
n8.
960
98P
aved
par
king
& ro
ofs
18.4
4079
Woo
ds/g
rass
com
b., G
ood,
HS
G D
27.4
0085
Wei
ghte
d A
vera
ge18
.440
Per
viou
s A
rea
8.96
0Im
perv
ious
Are
a
TcLe
ngth
Slo
peV
eloc
ityC
apac
ityD
escr
iptio
n(m
in)
(feet
)(ft
/ft)
(ft/s
ec)
(cfs
)4.
690
0.13
500.
33Sh
eet F
low
, New
Lan
dsca
peG
rass
: Den
se
n= 0
.240
P
2= 5
.75"
0.1
500.
1350
7.46
Shal
low
Con
cent
rate
d Fl
ow,
Pav
ed
Kv=
20.
3 fp
s1.
62,
089
0.13
5021
.84
38.6
0C
ircul
ar C
hann
el (p
ipe)
, Fro
m C
urb
to O
utle
tD
iam
= 18
.0"
Are
a= 1
.8 s
f P
erim
= 4.
7' r
= 0.
38'
n= 0
.013
Con
cret
e pi
pe, b
ends
& c
onne
ctio
ns6.
32,
229
Tota
l
Subc
atch
men
t 7S:
Tot
al C
lub
Port
ofin
o Pr
ojec
t Pos
t Dev
Run
off
=58
1.28
cfs
@
0.58
hrs
, V
olum
e=7.
730
af,
Dep
th=
1.18
"
Run
off b
y S
CS
TR
-20
met
hod,
UH
=SC
S, T
ime
Spa
n= 0
.00-
24.0
0 hr
s, d
t= 0
.01
hrs
Type
II 2
4-hr
-15
min
.PR
Tab
ular
1.0
0 hr
s N
ag 1
HR
-2yr
Rai
nfal
l=2.
50"
Are
a (a
c)C
ND
escr
iptio
n25
.700
98P
aved
par
king
& ro
ofs
53.0
1079
Woo
ds/g
rass
com
b., G
ood,
HS
G D
78.7
1085
Wei
ghte
d A
vera
ge53
.010
Per
viou
s A
rea
25.7
00Im
perv
ious
Are
a
TcLe
ngth
Slo
peV
eloc
ityC
apac
ityD
escr
iptio
n(m
in)
(feet
)(ft
/ft)
(ft/s
ec)
(cfs
)4.
690
0.13
500.
33Sh
eet F
low
, New
Lan
dsca
peG
rass
: Den
se
n= 0
.240
P
2= 5
.75"
0.1
500.
1350
7.46
Shal
low
Con
cent
rate
d Fl
ow,
Pav
ed
Kv=
20.
3 fp
s1.
62,
089
0.13
5021
.84
38.6
0C
ircul
ar C
hann
el (p
ipe)
, Fro
m C
urb
to O
utle
tD
iam
= 18
.0"
Are
a= 1
.8 s
f P
erim
= 4.
7' r
= 0.
38'
n= 0
.013
Con
cret
e pi
pe, b
ends
& c
onne
ctio
ns6.
32,
229
Tota
l
Pond
5P:
Wes
t Por
tofin
o Po
nd
Inflo
w A
rea
=51
.300
ac,
Inf
low
Dep
th =
1.
18"
for
Nag
1H
R-2
yr e
vent
Inflo
w=
378.
86 c
fs @
0.
58 h
rs,
Vol
ume=
5.03
8 af
Out
flow
=16
7.48
cfs
@
0.65
hrs
, V
olum
e=5.
038
af,
Atte
n= 5
6%,
Lag=
4.5
min
Prim
ary
=16
7.48
cfs
@
0.65
hrs
, V
olum
e=5.
038
af
Rou
ting
by S
tor-
Ind
met
hod,
Tim
e S
pan=
0.0
0-24
.00
hrs,
dt=
0.0
1 hr
s
Type
II 2
4-hr
-15
min
.PR
Tab
ular
1.0
0 hr
s N
ag 1
HR
-2yr
Rai
nfal
l=2.
50"
N
Recommended