final summary report drainage system evalutation phase ii · 2020. 9. 17. · drainage system...

CITY OF MESA DRAINAGE SYSTEM EVALUATION

FINAL SUMMARY REPORT OF FINDINGS

Prepared for:

The City of Mesa Public Works Department

Division of Engineering 20 East Main Street Mesa, AZ 85211

Prepared by:

Tetra Tech, Inc. Infrastructure Southwest Group

4600 South Mill Avenue Suite 200 Tempe, AZ 85282

(480) 491-1393

SEPTEMBER 1999

1

TABLE OF CONTENTS Section Page INTRODUCTION .......................................................................................................................... 1 STUDY CRITERIA ........................................................................................................................ 1

Level of Protection ............................................................................................................1 Roadway and Right of Way Capacities............................................................................. 1 Development and Retention Assumptions ........................................................................ 4 Drainage Boundary Determinations .................................................................................. 4 Hydrologic Methods .......................................................................................................... 4 Outfall Capacity Determinations........................................................................................ 5 Hydraulic Calculation Methods.......................................................................................... 5

STORM DRAIN LAYOUT AND ANALYSIS .................................................................................. 8 COST ESTIMATING AND PRIORITIZATION FOR NEW STORM

DRAINAGE SYSTEM ..................................................................................................... 12

LIST OF TABLES

Title Page Table 1: Summary of Right-of-Way Capacities............................................................................ 2 Table 2: Summary of Gutter Capacities....................................................................................... 3 Table 3: Summary of Hydrologic Calculations ............................................................................. 6 Table 4: Summary of Proportioned Discharges ........................................................................... 9 Table 5: Cost Summary of Proposed System............................................................................ 12 Table 6: Cost Summary of CIP Projects .................................................................................... 15 Table 7: Cost Summary of Spook Hill ADMP............................................................................. 15 Table 8: Cost Summary of East Mesa ADMP............................................................................ 16 Table 9: Cost Summary by Priority ............................................................................................. 17

LIST OF EXHIBITS Exhibit A: Existing and Currently Proposed Storm Drainage System - Front Pocket Exhibit B: Proposed Storm Drains and Drainage Area Map - Front Pocket

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LIST OF APPENDICES Appendix A: Hydrologic Calculation Sheets Appendix B: Outfall Capacity Calculation Sheets Appendix C: Summary of Proposed Storm Drain Diameters at Outfall Appendix D: Pipe-Size Summary Table Appendix E: Cost Estimate Sheets - Proposed System Appendix F: Cost Estimate Sheets - CIP Projects Appendix G: Cost Estimate Sheets - Spook Hill ADMP Appendix H: Spook Hill ADMP - Recommended Plan Appendix I: East Mesa ADMP - Preliminary Plan

0

INTRODUCTION The City of Mesa has contracted with Tetra Tech, Inc. to perform a City-wide drainage system evaluation that was conducted in two phases. Phase I of the study generally consisted of the identification of the existing and currently proposed storm drain systems throughout the City, identification of areas for analysis in Phase II of the study to: resolve existing drainage problems, identify sections of the City’s arterial streets to complete the arterial street storm drain system, and mapping of the existing and proposed systems. The Phase I effort resulted in a storm drain atlas of the existing and currently proposed storm drain system and the information necessary to determine the scope of additional hydrologic and hydraulic analysis required in Phase II to locate and size additional proposed storm drains to complete the City’s drainage system. The existing and currently proposed storm drain system is depicted in Exhibit A. Phase II consists of the study of the areas to resolve existing drainage problems and to complete the City’s arterial street drainage system. The new storm drain system layout with associated drainage areas is depicted in Exhibit B. The capacity of existing storm drain outfalls are evaluated and recommendations for proposed storm drain facilities are made. Cost estimates are developed and the systems are prioritized based on immediate and future needs. STUDY CRITERIA The criteria and methodologies used in Phase II of the study are as follows: Level of Protection In general, storm drains were sized such that the roadway will carry the 10-year storm with the runoff spread equal to the width of one lane and the 100-year storm will be contained in the right of way. Gutter capacity and right of way capacity were calculated and vary according to the slope of the arterial streets. If it was determined that the capacity of the existing storm drain outfall for the proposed system prevents achieving this level of protection, then the outfall capacity was used to size the proposed system and a lesser level of protection accepted. This capacity was referred to as the “pipe sizing discharge” in the pipe summary table. At the request of the City, replacement or modification of outfalls was not considered in the development of the proposed storm drain system. Roadway and Right of Way Capacities Roadways were analyzed assuming a 2% cross slope with a 14 foot width of inundation in the outside lane. Longitudinal slopes were developed from USGS maps and vary from 0.0025 ft/ft to 0.0109 ft/ft. The minimum default slope used was 0.0025 ft/ft. In developed areas of the City, right of way inundation was analyzed assuming on arterial streets, 55 feet of right of way on each side of the roadway centerline with two travel lanes in each direction and a center turn lane. In undeveloped areas of the City, the City’s current arterial street standard of 130 foot right of way was assumed. Flow depth for determining right of way capacity was assumed to be six inches higher than the back of sidewalk at the right of way line. Right of way capacities are summarized in Table 1 and gutter capacities are summarized in Table 2.

R.O.W. Width (ft) = 110Mannings Roughness "n" (weighted) = 0.022Cross Sectional Area (sq. ft.) = 58.2Hydraulic Radius "R" (ft) = 0.53

Longitudinal Slope (ft/ft)0.00250.00380.0090.0109

R.O.W. Width (ft) = 130Mannings Roughness "n" (weighted) = 0.020Cross Sectional Area (sq. ft.) = 62.6Hydraulic Radius "R" (ft) = 0.48


Table 1

Q=1.49/n x R 2/3 x S 1/2 x A

Q=1.49/n x R 2/3 x S 1/2 x A

177.0

Right of Way Discharge (R.O.W. Width = 110 feet)

129.1160.0

Discharge (cfs)

Summary of Right of Way Capacities

273.0300.0

Right of Way Discharge (R.O.W. Width = 130 feet)

244.9269.5

Discharge (cfs)143.0

Street Cross Slope (ft/ft) = 0.02Inverse of Street Cross Slope "Z' (ft/ft) = 50Mannings Roughness "n" (weighted) = 0.015Depth of Flow at Curb "d" (ft) = 0.28


6.06.6

4.0

Table 2

Q=0.56 x Z/n x S 1/2 x d 8/3

3.0

Discharge (cfs)

Summary of Gutter Capacities

City of Mesa Drainage System Evaluation Final Summary Report of Findings Phase II

3

Development and Retention Assumptions In developed areas of the City, historical photographs from 1979 were provided by the City and used to determine which areas of the City were constructed after 1977 when the City’s retention ordinance went into effect. Those portions of the City that were developed after 1977 were assumed to be fully retained for the 100-year, 2-hour storm except for the arterial street rights of way. In undeveloped areas of the City, it was assumed that undeveloped areas will be required to provide retention for the 100-year, 2-hour storm as development occurs and the areas were not considered to contribute runoff except for the arterial street rights of way. Agricultural areas were considered to be fully retained for the 100-year, 2-hour event. Drainage Boundary Determinations In general, the arterial streets were assumed to be drainage area boundaries. In addition, the various canals and railroad tracks were assumed to be drainage area boundaries. The drainage areas and associated concentration points are depicted in Exhibit B. Hydrologic Methods The rational method was used to determine runoff from all of the drainage areas studied. The minimum time of concentration used was ten (10) minutes. In general, the longest flow path in determining times of concentration was the perimeter of the drainage area with runoff flowing along the arterial streets to the concentration point. In cases where there is an existing pipe in an arterial street that would intercept a portion of the calculated runoff, the flow was still considered to be street flow in the time of concentration calculations since the quantity of runoff intercepted by the pipe is small in comparison to the flow that remains in the street. Runoff coefficients were developed for this analysis and are summarized as follows:

Golf Courses/ Parks ......................................................C=0.22 Residential (Single Family Residences)

Medium Density (2-5 DUA)......................................C=0.65 Med-Low Density (1-2 DUA)....................................C=0.60 Low Density (0-1 DUA)............................................C=0.55

Apartments ........................................................................... Older (pre-1979) ......................................................C=0.82 Newer ......................................................................C=0.70

Townhomes...................................................................C=0.73 Mobile Home Parks .......................................................C=0.80 Business/Commercial....................................................C=0.80 Arterial Streets ROW

130 ft. ROW.............................................................C=0.83 110 ft. ROW.............................................................C=0.82

Schools Buildings and Parking..............................................C=0.80 Playground Area (Primarily Grass)......................................................C=0.22 (Primarily Hard Surfaces) ........................................C=0.57


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Industrial Heavy ......................................................................C=0.92 Light.........................................................................C=0.82

Agricultural ....................................................................C=0.19 Land uses were determined from City of Mesa aerial photographs (1"=100' scale). The resistance coefficient ,k b, used in the equation for time of concentration was 0.05. This value is somewhat higher than recommended in the Maricopa County Drainage Manual however, the 0.05 value was used to reflect the resistance associated with flood flows occurring outside of the roadway prism and is considered to provide more realistic estimates of peak discharge. The drainage areas in residential areas were reduced by 25 % to account for backyard areas that are fenced with masonry walls that will not contribute runoff to the peak flow. Right of way runoff for arterial streets was calculated for three different scenarios as follows:

1. Arterial street with proposed pipe: the entire right of way is included in the runoff calculation.

2. Arterial street with existing pipe: the right of way is not included in the

runoff calculation.

3. Arterial street with no pipe: half of the right of way area was included in the runoff calculation.

A summary of the hydrologic calculations is included in Table 3. Individual calculations sheets for each drainage area are included in Appendix A. Outfall Capacity Determinations Existing storm drains that will serve as outfalls for the proposed systems were analyzed to determine their capacity. The City’s storm drain database was used to establish invert elevations of existing storm drains. The starting hydraulic grade line for the proposed storm drains was assumed to be located one foot above the top of the pipe at the connection point with the associated outfall. In cases where the connection point is to be at an existing headwall, the starting hydraulic grade line was taken to be at the top of the pipe. Outfall capacity calculations for existing outfalls are included in Appendix B. Hydraulic Calculation Methods The WSPG computer program developed by the Los Angeles County Flood Control District was used for storm drain hydraulic calculations.

Q10 Q100

5B-combined 0.30 NO 0.76 6,700 49.8 2.2 178 2735C 0.15 NO 0.73 2,650 27.2 1.6 157 2316C 0.36 NO 0.68 4,300 37.5 1.9 193 28812B 0.45 NO 0.68 8,800 60.6 2.4 246 37015D 0.27 NO 0.69 5,810 45.8 2.1 108 16120D 0.18 NO 0.71 5,030 41.8 2.0 141 200

21B(1) 0.32 NO 0.80 6,480 49.0 2.2 230 34821B(2) 0.19 NO 0.82 5,280 43.0 2.0 178 25526D(1) 0.03 NO 0.69 2,650 27.2 1.6 30 44

26D(1)-combined 1.09 NO 0.61 14,790 89.2 2.8 267 37826D(2) 0.03 NO 0.52 1,325 17.3 1.3 37 5626D(3) 0.04 NO 0.77 1,325 17.3 1.3 74 110

27D 0.26 NO 0.71 2,600 26.9 1.6 41 6028A-combined 0.45 NO 0.69 11,560 73.9 2.6 223 32329B-combined 0.65 NO 0.79 8,950 61.5 2.4 483 723

29D 0.26 NO 0.79 5,200 42.8 2.0 245 35834A 0.40 NO 0.59 6,950 51.7 2.2 171 253

34B(1) 0.13 NO 0.59 3,850 34.9 1.8 85 12334B(2) 0.16 NO 0.71 3,850 34.9 1.8 62 90

35B 0.48 NO 0.51 5,280 42.5 2.1 89 13436A(1) 0.05 NO 0.75 4,000 35.8 1.9 49 7336A(2) 0.12 NO 0.68 2,800 28.0 1.7 104 154

36B 0.38 NO 0.67 5,650 44.7 2.1 271 40337B 0.13 NO 0.80 3,300 31.4 1.8 159 23842A 0.20 NO 0.67 4,000 35.8 1.9 68 10242B 0.46 YES 0.83 1,150 16.0 1.2 10 1542C 0.22 YES 0.82 5,290 43.0 2.0 19 2843B 1.00 YES 0.82 5,280 42.7 2.1 33 4944A 0.04 NO 0.69 1,000 14.6 1.1 60 8844B 0.45 NO 0.69 4,200 36.8 1.9 266 39045B 0.46 NO 0.70 6,900 51.5 2.2 300 44651B 0.84 NO 0.64 7,600 54.9 2.3 307 45652D 0.24 NO 0.69 4,500 38.6 1.9 135 19853B 0.26 NO 0.68 3,600 33.4 1.8 189 27560B 0.32 NO 0.71 5,600 44.5 2.1 79 11761A 0.48 NO 0.79 6,500 49.1 2.2 290 438

62B(1) 0.06 NO 0.57 2,350 25.1 1.6 39 5962B(2) 0.20 NO 0.82 2,100 23.5 1.5 11 16

63B 0.10 YES 0.82 2,300 24.8 1.5 13 2066B 0.74 YES 0.82 8,500 59.5 2.4 32 4868A 0.50 YES 0.83 5,280 43.0 2.0 13 1973B 0.50 YES 0.83 4,700 51.7 1.5 20 3076B 0.13 YES 0.82 3,750 34.0 1.8 12 1977B 0.56 NO 0.80 7,280 53.5 2.3 453 67183B 1.00 YES 0.83 5,280 36.2 2.4 29 4384A 0.50 YES 0.83 5,280 25.0 3.5 18 2889B 0.69 YES 0.82 5,280 20.6 4.3 34 51

89B-combined 0.74 YES 0.82 8,280 27.6 5.0 55 8191B 1.00 NO 0.63 6,000 24.5 4.1 309 46497B 0.07 YES 0.83 900 7.0 2.2 12 1898B 0.62 YES 0.83 5,280 20.6 4.3 41 6299B 0.74 YES 0.83 9,300 29.6 5.2 58 88

Drainage Area (sq.

miles)

Peak Discharge (cfs)

Summary of Hydrologic CalculationsTable - 3

Concentration Point

Length of Longest Flow

Path (ft)

100% Retention1

Time of Concentration

(min)

Average Velocity2

(ft/sec)

Weighted Runoff

Coefficient

Q10 Q100

Drainage Area (sq.

miles)

Peak Discharge (cfs)

Summary of Hydrologic CalculationsTable - 3

Concentration Point

Length of Longest Flow

Path (ft)

100% Retention1

Time of Concentration

(min)

Average Velocity2

(ft/sec)

Weighted Runoff

Coefficient100A 0.61 YES 0.83 2,650 13.4 3.3 26 39108B 1.46 YES 0.83 10,560 32.5 5.4 63 92

109A-combined 1.89 NO 0.80 13,210 37.6 5.9 147 227117D 0.26 NO 0.78 8,930 28.8 5.2 183 275118B 1.00 NO 0.63 10,560 32.5 5.4 191 281120B 1.00 YES 0.83 5,280 25.0 3.5 36 55124B 0.99 NO 0.59 7,275 25.4 4.8 262 394126B 1.00 NO 0.70 10,560 32.5 5.4 208 306127B 0.13 YES 0.83 2,800 16.7 2.8 25 37131B 0.05 YES 0.83 1,800 10.7 2.8 17 25132B 1.00 NO 0.58 10,560 32.5 5.4 701 1032133A 0.22 NO 0.63 3,500 16.0 3.7 247 367

133A-combined 1.26 NO 0.59 11,780 35.1 5.6 833 1210134B 0.41 YES 0.83 2,600 13.2 3.3 26 39134D 0.21 YES 0.83 3,000 14.5 3.4 29 42135B 0.50 YES 0.83 5,280 25.0 3.5 36 55139B 0.31 YES 0.83 1,400 9.4 2.5 16 24140B 1.00 NO 0.66 10,560 32.5 5.4 296 436141A 0.29 NO 0.65 3,500 16.0 3.7 283 420

141A-combined 1.57 NO 0.65 14,000 39.4 5.9 428 623141D 0.30 NO 0.65 5,200 20.5 4.2 314 469142B 0.14 NO 0.65 2,500 12.9 3.2 118 179143B 0.50 YES 0.83 5,280 25.0 3.5 36 55313B 1.00 YES 0.83 5,280 25.0 3.5 72 110

312B-combined 2.81 YES 0.83 14,060 48.2 4.9 110 162314B 1.00 YES 0.83 5,280 25.0 3.5 72 110

317B-comb 2.50 YES 0.83 17,060 54.6 5.2 66 99

1 One-hundred percent retention indicates those drainage areas with no development prior to 1977.For this study, it was assumed that runoff from these drainage areas is generated from arterial street right of ways only.

2 Average velocity is calculated by dividing the Length of the Longest Flow Path (L ) by the Time of Concentration (T c ).


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STORM DRAIN LAYOUT AND ANALYSIS Storm drain systems necessary to complete the City’s arterial street drainage system, to address drainage problem areas, and the CIP project areas were developed and analyzed. The level of detail for the storm drain layout consists of the identification of the required pipe size, locating the storm drain along the existing arterial street alignments and setting the pipe slope at the slope of the existing terrain. Outfall capacity determinations were made and considered when determining the pipe sizes. The work under this contract did not include the establishment of storm drain profiles or the identification of utility conflicts. Storm drain pipe sizes at the outfall of each system is included in the storm drain summary table in Appendix C. In cases where the drainage areas are bounded by either existing or proposed storm drains on both the south and west sides, the computed discharge from that drainage area was proportioned to each storm drain according to the respective lengths of storm drain pipe in each side of the drainage area. In the proposed pipe sizing calculations this method of proportioning runoff was used for existing storm drains regardless of capacity. A summary of proportioned discharges is included in Table 4. In addition, discharges for proposed storm drains were “stepped down” proportionately at quarter mile points to account for the reduction in drainage area size progressing upstream. This method was used since there was no detailed topographic information available for this study that would be necessary for the exact determination of intermediate concentration points and associated discharges. The “stepped down” discharges and pipe sizes are included in the pipe size summary table in Appendix D. If the outfall capacity for the drainage area controls the pipe sizing, the pipe size is stepped down only when the contributing runoff becomes less than the outfall capacity. On the storm drain exhibit (Exhibit B), the proposed outfalls are named according to the City’s quarter section numbers and the direction the pipe is flowing. The McKellips Road storm drain plans are used for several outfalls and these are named by station along McKellips Road. Existing outfalls are named according to the City’s storm drain database. Drainage area designations are named according to the City’s quarter section numbers. The storm drain layout also included the approximate number of required manholes based on the City’s standard manhole spacing. The number of required catch basins and laterals was estimated assuming a spacing of 300 feet. No detailed hydraulics were performed to determine catch basin spacing. Storm drain lateral lengths were established by measuring the pavement width of the roadway and subtracting 8 feet to account for the width of the catch basins and mainline pipe. Quantities for pavement replacement were determined using MAG specification 336.4(A). The new storm drain system is summarized in the pipe size summary table in Appendix D and on Exhibit B.

Table - 4 Proportioned Discharge for Designing Proposed Storm Drain

Concentration Point Location of Proposed Storm Drain

Stapley Drive: Main Street to Broadway Broadway: Harris to Stapley

Gilbert Road: Brown to McKellips Brown: Lindsay to Gilbert

525 1 135 1 198 1 NA I NA 1 135 1 198 1 University: Lindsay to approx. 25th Street

1 t I I I

I 1088 I 63 I 92 I N A I NA I 63 1 92 I University: Salt-Gila Aqueduct to Sossaman 1 109A-combined ( 147 I 227 I 147 I 227 I NA I NA I Sossaman: University to Apache Boulevard


Concentration Point I QIO (cfs)

%charge for Designing Propose Ah Street I East-Wt

d Storm Drain

Location of Proposed Storm Drain

NA 1 Tempe Canal Storm Sewer: Broadway Road to Main Street

288 1 8th Avenue at the Tempe Canal

332 University Drive: Dobson Road to Alma School Road

Baseline: Alma School Road to Extension

200 1 University Drive: East of Extension to Country Club Drive

358 89 134 49 73 NA NA Mesa Drive: Tempe Canal to McKellips

36A(l) 49 73 5 8 NA NA Mesa Drive: Tempe Canal to Brown Road

42A 1 68 1 102 1 40 1 60 1 NA I NA I Stapley: Red Mountain Freeway to Lehi Road

Stapley Drive: Consolidated Canal to University


Concentration Point Q10 (cfs) QIOO (cfs) Location of Proposed Storm Drain

Broadway Road: Crismon to Ellsworth Southern: Ellsworth to Hawes Hawes: Baseline to Guadalupe

University: Crismon to Salt-Gila Aqueduct Southern: Crismon to Ellsworth

Ellsworth: US 60 to Baseline Road University: Signal Butte to Crismon Road

Crismon Road: 114 mile north of Brown to approx. Boise St.

I I I I I I I Road


11

COST ESTIMATING AND PRIORITIZATION FOR NEW STORM DRAINAGE SYSTEM Cost estimates for the new storm drain system were developed and include mainline pipe, manholes, laterals, catch basins, headwalls, and pavement replacement. The cost information is presented herein in Table 5 which identifies the costs of the various systems. Cost information for storm drain systems studied by others was gathered and incorporated into this study. Table 6 summarizes the cost information from CIP projects studied by others. Table 7 summarizes the cost information for the Spook Hill ADMP and Table 8 summarizes the cost information for the East Mesa ADMP. Cost estimating sheets for each proposed system, CIP projects studied by others, and the Spook Hill ADMP are included in Appendices E,F, and G respectively. No cost sheets were prepared for the East Mesa ADMP since there were no detailed quantities available. In the case of the East Mesa ADMP, the costs were taken directly from that report without adjustment. Portions of the Spook Hill system were eliminated to account for the proposed Las Sendas drainage improvements to be constructed and paid for by private developers. The recommended plan for the Spook Hill ADMP and the East Mesa ADMP are provided in Appendices H and I, respectively. The storm drain systems were prioritized in three (3) categories to establish which systems are needed to meet immediate needs and which systems are needed to meet future needs. Immediate need is considered to be a system in a developed area of the City that is needed to address an existing drainage problem or to complete the City’s arterial street drainage system, and is considered “high” priority. A future need is considered to be a system located in the undeveloped areas of the City, and is considered “low” priority. In areas of partial development, the systems were assigned a “medium” priority. The Spook Hill System was not prioritized since it is planned to be re-studied by the Maricopa County Flood Control District in the near future. In the following cost summary tables, the systems prioritized as high priority are identified with the number 1. Systems prioritized as medium priority are identified with the number 2, and systems prioritized as low priority are identified with the number 3. Cost summaries by priority level are provided in Table 9. Also included in Table 9 is the total for all storm drain costs on a city-wide basis.

TABLE 5 - COST ESTIMATES FOR PROPOSED STORM DRAIN SYSTEM

System

Priority Rating

Cost

Tempe Canal Storm Sewer from Broadway Road to Main Street

(1)

$1,418,229

Main Street at the Tempe Canal

(1)

$296,595

8th Avenue at the Tempe Canal

(1)

$1,891,202

University Drive from Dobson Road to Alma School Road

(1)

$1,425,276

Baseline Road from Alma School Road to Extension

(1)

$719,375

University Drive from east of Extension to Country Club Drive

(1)

$245,673

Alma School Road from railroad tracks to Main Street

(1)

$307,355

Alma School Road from railroad tracks to Broadway Road

(1)

$241,907

Lehi from Center Street to Gilbert Road

(1)

$3,992,180


12

Center Street from Bates Road to Lehi (1) $318,006 Center Street from Bates Road to McKellips

(1)

$315,981

TABLE 5 - COST ESTIMATES FOR PROPOSED STORM DRAIN SYSTEM - Continued

System

Priority Rating

Cost

Center Street from the Tempe Canal to McLellan

(1)

$521,357

Brown Road from Country Club Drive to Stapley

(1)

$1,933,578

Broadway Road from Mesa Drive to Country Club Drive

(1)

$1,361,124

Center Street from Broadway Road to 2nd Street

(1)

$499,203

Mesa Drive from Lehi to Red Mountain Freeway

(1)

$295,326

Mesa Drive from Bates Road to Lehi

(1)

$279,086

Mesa Drive from Bates Road to McKellips

(1)

$229,433

Mesa Drive from the Tempe Canal to McKellips

(1)

$1,081,917

Mesa Drive from the Tempe Canal to Brown Road

(1)

$88,128

Mesa Drive from 8th Street to Brown Road

(1)

$368,253

Mesa Drive from 8th Street to University

(1)

$560,561

Mesa Drive from 2nd Street to Broadway Road

(1)

$514,472

Stapley from Red Mountain Freeway to Lehi Road

(1)

$435,726

Stapley from the Southern Canal to McKellips

(1)

$141,980

Stapley from Brown Road to McKellips

(1)

$1,034,289

Stapley Drive from the Consolidated Canal to Brown Road

(1)

$166,050

University Drive from the Consolidated Canal to Stapley

(1)

$864,527

Stapley Drive from the Consolidated Canal to University Drive

(1)

$864,527

Broadway Road from Harris to Stapley

(1)

$636,255

Stapley Drive from Main Street to Broadway Road

(1)

$537,948

Brown Road from Lindsay to Gilbert Road

(1)

$922,509

Gilbert Road from Brown Road to McKellips

(1)

$922,509

University Drive from Lindsay to approximately 25th Street

(1)

$461,255

Broadway Road from the Consolidated Canal to Gilbert Road

(1)

$650,876

Lindsay Road from 8th Street to University Drive

(1)

$461,255

University Drive from the Eastern Canal to Lindsey Road

(1)

$717,593

Main Street from Val Vista to Lindsay Road

(1)

$1,011,285

Southern Avenue from the Consolidated Canal to Lindsay

(1)

$123,309

Southern Avenue from the Consolidated Canal to 32nd Street

(2)

$261,239

Lindsay Road from US 60 to Baseline Road

(1)

$295,475

Val Vista from the Southern Canal to McKellips

(2)

$1,545,548

Val Vista from Brown Road to Adobe Road

(2)

$480,695


13

Greenfield Road from the Red Mountain Freeway to McDowell Road

(3) $828,549

University Drive from the RWCD Canal to Greenfield Road

(1)

$461,255

TABLE 5 - COST ESTIMATES FOR PROPOSED STORM DRAIN SYSTEM - Continued

System

Priority Rating

Cost

Broadway Road from the RWCD Canal to Greenfield Road

(1)

$1,893,294

Higley Road from McKellips to Brown Road

(1)

$376,947

Higley Road from Brown Road to Adobe Road

(1)

$364,473

McDowell Road from Power Road to Recker Road

(2)

$1,164,038

Recker Road from McKellips to 1/4 mile north of Brown Road

(1)

$728,109

Power Road from the Red Mountain Freeway to McDowell Road

(2)

$522,437

Power Road from McDowell Road to McKellips

(2)

$947,457

Power Road from McKellips to Brown Road

(2)

$997,110

Power Road from Brown Road to Adobe Road

(2)

$482,720

University Drive from Salt-Gila Aqueduct to Sossaman Road

(2)

$2,276,019

Sossaman Road from University to Apache Boulevard

(1)

$580,001

Broadway Road from Crismon to Ellsworth

(2)

$1,392,174

Southern Avenue form Ellsworth Road to Hawes Road

(1)

$1,140,642

Hawes Road from Baseline Road to Guadalupe Road

(2)

$540,797

University Drive from Crismon to the Salt-Gila Aqueduct

(1)

$1,003,361

Southern Avenue from Crismon to Ellsworth Road

(1)

$1,183,410

Ellsworth Road from US 60 to Baseline Road

(2)

$556,497

University Drive from Signal Butte to Crismon

(2)

$1,532,844

Crismon from 1/4 mile north of Brown to 1/4mile south of University

(1)

$2,928,825

Southern Avenue from Crismon to 1/2 mile east of Crismon

(2)

$482,720

Southern Avenue from Signal Butte Road to 1/2 mile west of Signal Butte Road

(3)

$482,720

Baseline Road from Signal Butte Road to Crismon

(3)

$988,362

University Drive from Meridian to Signal Butte Road

(2)

$1,081,917

Signal Butte Road from 1/4 mile north of Brown to Apache Boulevard

(1)

$1,913,315

Broadway Road from Meridian to Mountain Road

(1)

$693,725

Southern Avenue from the Salt-Gila Aqueduct to Signal Butte Road

(3)

$642,047

Baseline Road from Meridian to Signal Butte Road

(3)

$973,863

Elliot from Ellsworth Road to the RWCD Canal

(3)

$2,942,690

Sossaman from Guadalupe to Elliot

(3)

$1,033,965


14

Hawes Road from Guadalupe to Elliot (3) $1,033,965 Signal Butte Road from Baseline to Elliot

(3)

$2,314,575

TOTAL COST OF PROPOSED SYSTEM

$67,923,890

TABLE 6 - COST ESTIMATES FOR CIP PROJECTS STUDIED BY OTHERS

System

Priority Rating

Cost

Ellsworth Road from Germann Road to Baseline Road

(3)

$6,112,510

Power Road from Baseline Road to the East Maricopa Floodway

(2)

$1,071,839

Main Street from Sossaman Road to 96th Street

(1)

$866,936

Mesa Drive from the Superstition Freeway to Southern Avenue

(1)

$304,277

Gilbert Road from the Red Mountain Freeway to McKellips Road

(1)

$862,502

Baseline Road from 1900 ft. E. of Stapley Road to the Consolidated Canal

(2)

$2,354,690

Gilbert Road from Broadway Road to Main Street

(1)

$332,849

Broadway Road from Power Road to the East Maricopa Floodway

(1)

$6,552,234

Broadway Road from Sossaman Road to Hawes Road

(1)

$1,939,950

Southern Avenue from Sossaman Road to Hawes Road

(2)

$3,167,101

Hawes Road from Main Street to the Superstition Freeway

(1)

$3,874,265

TOTAL COST OF CIP PROJECTS STUDIED BY OTHERS

$27,439,153

TABLE 7 - COST ESTIMATES FOR SPOOK HILL ADMP

System

Cost

Indian School Road Outfall

$264,408

Osborn Road Outfall

$226,872

Quenton Street Outfall

$614,376

McDowell Road Outfall east of Sossaman Road

$861,297

Red Mountain Freeway Outfall Channel

$2,376,115

80th Street Outfall

$288,067

Hawes Road Outfall

$312,388

88th Street Outfall

$536,556

Freeway Basin 1

$175,272

Freeway Basin 2

$175,272

McLellan Road Outfall

$494,426


15

Ellsworth Road Outfall

$602,453

Usery Park Levee

$416,086

Quenton Street Collector Channel

$175,674

Ravens Roost Dam and Outfall

$1,588,645

McDowell Road Collector Channel

$476,514

TABLE 7 - COST ESTIMATES FOR SPOOK HILL ADMP - Continued

System

Cost

Hermosa Vista Collector Channel

$379,086

TOTAL COST FOR SPOOK HILL ADMP

$9,963,507

TABLE 8 - COST ESTIMATE FOR EAST MESA ADMP

System

Priority Rating

Cost

CAP Detention Basin 1

(1)

$1,318,422

CAP Detention Basin 2 and Outlet

(1)

$2,195,666


(1)

$1,615,702


(1)

$4,619,029

Parkwood Ranch Detention Basin & Outlet Channel

(2)

$2,577,031

Elliot Detention Basin

(3)

$6,166,609

Elliot Channel Phase I

(3)

$14,269,446

Powerline Floodway - East of Existing North Perimeter Channel

(3)

$1,954,741

CAP Detention Basin 3 Outlet & Channel

(1)

$608,282

Apache Channel

(1)

$3,880,946

Broadway Channel

(1)

$6,133,233

Parkwood Ranch Channel - North of Parkwood Ranch Detention Basin

(3)

$962,293

Sunland Springs Channel and Siphon Draw Detention Basin

(1)

$12,115,573

Elliot Channel Phase 2

(3)

$4,778,276

Crismon Channel and Lateral

(3)

$6,303,319

Pecos North & South Detention Basins

(3)

$15,493,011

Meridian North Channel

(3)

$701,744

Pecos Channel

(3)

$13,622,219

Powerline Floodway - West of Existing North Perimeter Channel

(3)

$7,477,119

Powerline Detention Basin

(3)

$1,374,647

Meridian South Channel

(3)

$1,684,506


16

Pecos Channel Laterals (3) $1,116,135 Rittenhouse Channel and Laterals

(3)

$2,771,004

TOTAL COST FOR EAST MESA ADMP

$113,738,953


17

TABLE 9 - COST SUMMARY BY PRIORITY

System

Priority 1

Priority 2

Priority 3

Not

Prioritized New Proposed Storm Drain System

$42,418,942

$14,264,212

$11,240,736

CIP Projects Studied By Others

$14,733,013

$6,593,630

$6,112,510

Spook Hill ADMP

$9,963,507

East Mesa ADMP

$32,486,853

$2,577,031

$78,675,069

Total by Priority

$89,638,808

$23,434,873

$96,028,315

$9,963,507

GRAND TOTAL

$219,065,503

CITY OF MESA DRAINAGE SYSTEM EVALUATION - PHASE II Rational Method Calculation Sheet Source: Drainage Design Manual for Maricopa County, Arizona

Concentration Point 56 - combined Quarter Section Map Numbers 5B, 5C, 5D

Outfall ID

Drainage Area 0.22 sq miles Areas with 100% Retention 0.08 sq miles

Total Area 0.30 sq miles

Step 1: Determine Weighted Runoff Coefficient (C)

Description of Land Use Runoff Coefficient (C)

Apartments (newer) 1 0.70 1 7 13.1 Mobile Home Park 0.80 8 16.7 ROW 0.82

Total 142.5 acres

131.75 acres (reduced)* Weighted Runoff Coefficient* = Q;L(i

Ster, 2: Determine Time of Concentration /T,) - - - - - -- -

7, = f f . 4 ~ 0 . 5 ~ ~ 0 . 5 2 ~ 4 . 3 f ~ - 0 . 3 8

L = Length of the Longest Flow Path in feet ........................... 6,700 feet

............................... Kb = Watershed Resistance Coefficient** 0.050 ...................................... S = Watercourse Slope in feetlmile 13.2 Wmile

Iterative Process to Determine Tc and Rainfall lntensity (I)

Ster, 3: Calculate Peak Discharae (Q1

.......................................... C = Runoff Coefficient (weighted) 0.76

................... I = Rainfall Intensity in incheslhour ( I O-yr storm). 1.78 inlhr

................... = Rainfall Intensity in incheslhour (100-yr storm) 2.73 inlhr

................ A = Drainage Area* (contributing areas only) in acres 131.8 acres ........................................... Qlo = IO-yr Peak Discharge in cfs 178 cfs

Qioo = 100-yr Peak Discharge in cfs .......................................... 273 cfs

* The drainage area is reduced by 25% of the medium density and medium to low density residential areas fo account for retention occuring

within walled back yards. This reduced drainage area Is used when calculating the weighted runoff coefficient,

as well as the peak discharge.

**For fhe purposes of this study, the watershed resistance coefficient is constant for all drainage areas.

CITY OF MESA DRAINAGE SYSTEM EVALUATION - PHASE I1 Rational Method Calculation Sheet Source: Drainage Design Manual for Maricopa County, Arizona

Concentration Point Quarter Section Map Numbers

Outfall ID Drainage Area

Areas with 100% Retention Total Area

0.14 sq miles

0.01 sq miles 0.15 sq miles



Total 90.4 acres

79.65 acres (reducedy Weighted Runoff Coefficient* =

Step 2: Determine Time of Concentration (T,)


............................... K b = Watershed Resistance Coefficient** 0.050 ...................................... S = Watercourse Slope in feetlmiie 13.2 Wmile

Iterative Process to Determine T, and Rainfall lntensity (I)

.-s - I - -

T C - ...

Step 3: Calculate Peak Discharge (Q)

Q = CIA

C = Runoff Coefficient (weighted) .......................................... 0.73

.................... I

= Rainfall Intensity in incheslhour ( I O-yr storm) 2.70 inlhr

= Rainfall Intensity in incheslhour (100-yr storm) ................... 3.96 inlhr

A = Drainage Area* (contributing areas only) in acres ................ 79.7 acres ........................................... Qlo = 10-yr Peak Discharge in cfs 157 cfs .......................................... Qioo = 100-yr Peak Discharge in cfs 231 cfs

* The drainage area is reduced by 25% of the medium density and medium to low density residential areas to account for retention occuring

within walled back yards. This reduced drainage area is used when calculating the welghted runoff coeMcient,


**For the purposes of this study, the watershed resistance coefficient is constant for all drainage areas.

c l n OF MESA DRAINAGE SYSTEM EVALUATION - PHASE II Rational Method Calculation Sheet Source: Drainage Design Manual for Maricopa County, Arizona

Concentration Point 6C Quarter Section Map Numbers 6A, 6C

Outfall ID Drainage Area 0.26 sq miles

Areas with 100% Retention 0.10 sq miles Total Area 0.36 sq miles

Step I: Determine Weighted Runoff Coefficient (C)

area S u b # I (acres) Area I Description of Land Use Runoff Coefficient (C)

Commercial

Total 164.9 acres - -

132.4 acres (reduced)" Weighted Runoff Coefficient* = 124i8.

Step 2: Determine Time of Concentration (7,)

........................... L = Length of the Longest Flow Path in feet 4,300 feet

............................... Kt? = Watershed Resistance Coefficient** 0.050 ...................................... S = Watercourse Slope in feetimile 13.2 ftlmile


- I

- - -

7°C - -

Step 3: Calculate Peak Discharge (9)

Q = CIA


................... I = Rainfall Intensity in incheslhour (1 0-yr storm). 2.15 inlhr = Rainfall Intensity in incheslhour (100-yr storm) ................... 3.20 inlhr

A = Drainage Area* (contributing areas only) in acres ................ 132.4 acres ........................................... Qlo = ?O-yr Peak Discharge in cfs 193 cfs

.......................................... QIOO = 100-yr Peak Discharge in cfs 288 cfs

* The drainage area is reduced by 25% of the medium density and medium to low density residential areas to account for refention occuring

within walled back yards. This reduced drainage area is used when calculating the weighted runoff coefficient,


"For the purposes of this study, the watershed resistance coefficient is constant for all drainage areas.

CITY OF MESA DRAINAGE SYSTEM EVALUATION - PHASE il Rational Method Calculation Sheet Source: Drainage Design Manual for Maricopa County, Arizona




12B

12B, 12D MH-3893

0.45 sq miles



area Sub" # I (acres) Area I Description of Land Use Runoff Coefficient (C)

Total 286.8 acres

233.1 acres (reduced)* Weighted Runoff Coeficient* = Qta3


1 = Length of the Longest Flow Path in feet, .......................... 8,800 feet

............................... K b = Watershed Resistance Coefficient** 0.050 ...................................... S = Watercourse Slope in feevmile 13.2 Wmile

Iterative Process to Determine 7, and Rainfall Intensity ( I )


Q = CIA

C = RunoffCoefkient(weighted) .......................................... 0.68

.................... I = Rainfall Intensity in inches/hour (10-yr storm) 1.55 inlhr


A = Drainage Area* (contributing areas only) in acres ................ 233.1 acres ........................................... Qlo = 10-yr Peak Discharge in cfs 246 cfs

Q~oo = 100-yr Peak Discharge in cfs .......................................... 370 cfs

* n7e drainage area is reduced by 25% of the medium density and medium to low density residential areas to account for retention occuring




C I N OF MESA DRAINAGE SYSTEM EVALUATION - PHAS Rational Method Calculation Sheet Source: Drainage Design Manual for Maricopa County, Arizona

Concentration Point 15D Quarter Section Map Numbers



0.16 sq miles 0.1 1 sq miles 0.27 sq miles



Total 104.6 acres

82.9 acres (reduced)* Weighted Runoff Coefficient* =



............................ K b = Watershed Resistance Coefficient** 0.050

S = Watercourse Slope in feetlmile ....................................... 13.2 Wmile

Iterative Process to Determine Tc and Rainfall Intensity (I)


Q = CIA

C = Runoff Coefficient (weighted) .......................................... 0.69 ....................

I = Rainfall Intensity in incheslhour (10-yr storm) 1.90 inlhr

= Rainfall Intensity in incheslhour (1 00-yr storm). .................. 2.83 inlhr



* The drainage area is reduced by 25% of the medium density and medium to low density residential areas to account for retention occuring within walled back yards. This reduced drainage area is used when calculating the weighted runoff coefficient,






Areas with 100% Retention

Total Area

0.18 sq miles

sq miles sq miles


Total

(acres) Area I Description of Land Use Runoff Coefficient (C}

115.9 acres

95.4 acres (reduced)* Weighted Runoff Coefficient* = QAZl



.......... .............. K b = Watershed Resistance Coefficient** .... 0.050 ...................................... S = Watercourse Slope in feetlmile 13.2 @mile

Iterative Process to Determine T, and Rainfall lntensity (I}

Sterr 3: Calculate Peak Discharae (Q)

Q = CIA

C = Runoff Coefficient (weighted) ......................................... 0.71

................... I = Rainfall Intensity in incheslhour (1 0-yr storm). 2.1 0 inlhr



.......................................... Qioo = 100-yr Peak Discharge in cfs 200 cfs

* The drainage area is reduced by 25% of the medium density and medium to low density residentla! areas to account for retention occuring



**For the purposes of this study, the watershed resistance coefficient is constant for aN drainage areas.

C l N OF MESA DRAINAGE SYSTEM EVALUATION - PHASE I1 Rational Method Calculation Sheet Source: Drainage Design Manual for Maricopa County, Arizona

Concentration Point 21 B(l) Quarter Section Map Numbers 21 B, 21 D (North of Railroad Tracks)

Outfall ID MH-3343





Total 163.8 acres




............................... Kb = Watershed Resistance Coefficient** 0.050 ...................................... S = Watercourse Slope in feetlmile 13.2 ft/mile


TC = l ~ i m e of Concentration in minutes 1 47.90 1 49.14 1 49.01 1 I Step 3: Calculate Peak Discharge (Q)

Q = CIA

C = Runoff Coefficient (weighted). ......................................... 0.80

.................... I = Rainfall Intensity in inchesthour (IO-yr storm) 1.80 inthr

.................. = Rainfall Intensity in inchesthour ( I OO-yr storm). 2.72 inthr

A = Drainage Area* (contributing areas only) in acres.. .............. 160.1 acres .......................................... Qqo = IO-yr Peak Discharge in cfs 230 cfs

.......................................... Qzoo = 100-yr Peak Discharge in cfs 348 cfs

* The drainage area is reduced by 12.5% of the medium density and medium to law density residential areas to accounf for retention occuring








21 B(2) (South of Railroad Tracks) 218,22D MH-3343

0.17 sq miles 0.02 sq miles 0.19 sq miles


area # (acres) Sub- I Area I Description of Land Use Runoff Coefficient (C)

Total 105.8 acres

NA acres (reduced)" Weighted Runoff Coefficient* =



............................ K b = Watershed Resistance Coefficient*" 0.050 S = Watercourse Slope in feetlmile ..................................... 13.2 ftlmile


= Adjusted Intensity in incheslhour 2.92 2.94 TC = Time of Concentration in minutes 43.08 42.98


Q = CIA

C = Runoff Coefficient (weighted). ....................................... 0.82

.................. I = Rainfall Intensity in incheslhour (10-yr storm) .. 2.05 inlhr

................. = Rainfall Intensity in incheslhour (100-yr storm).. 2.94 inlhr

................ A = Drainage Area* (contributing areas only) in acres 105.8 acres ........................................... Qlo = 10-yr Peak Discharge in cfs 178 cfs


* The drainage area is reduced by 25% of the medium density and medium to low density residential areas to account for retention occurfng

within walled back yards. This reduced dminage area is used when calculating the weighted runoff coefficient,

as well as fhe peak discharge.



Concentration Point 26D(I )-combined

Quarter Section Map Numbers 26D, 34B, 34A, 34C, 34D, 42A, 426 Outfall ID




area Sub- # I (acres) Area I Description of Land Use Runoff Coefficient (C)

Residential - low densit

Total 472.6 acres

372.6 acres (reduced)* Weighted Runoff Coefficient* = QdZ.


L = Length of the Longest .Flow Path in feet ........................... 14,790 feet

............................. K b = Watershed Resistance Coefficient**.. 0.050 S = Watercourse Slope in feetlmile ...................................... 13.2 Wmile


- - I - -

T c - -


Q = CIA


................... I = Rainfall Intensity in incheslhour (1 0-yr storm). 1 .I 8 inlhr


A = Drainage Area* (contributing areas only) in acres ................ 372.6 acres ........................................... Qlo = IO-yr Peak Discharge in cfs 267 cfs


* The drainage area is reduced by 25% of the medium density and low density residential areas to account for retention occuring

within walled and depressed back yards. This reduced drainage area is used when calculafing the weighted runoff coefficient,



CITY OF MESA DRAINAGE SYSTEM EVALUATION - PHASE I1 Rational Method Calculation Sheet Source: Drainage Design Manual for Maricopa County, Arizona

Concentration Point 26D(2) Quarter Section Map Numbers 26D



Step I : Determine Weighted Runoff Coefficient (C)

Sub- I Area area # I (acres)

Total 20.4

NA

Description of Land Use I Runoff Coefficient (C) I

I 1

acres

acres (reduced)* Weighted Runoff Coefficient* =


T, = 11.4 ~ 0 . 5 ~ ~ 0 . 5 2 ~ - 0 . 3 1 -0.38 I


............................... K b = Watershed Resistance Coefficient** 0.050 ...................................... S = Watercourse Slope in feetlmile 13.2 Wmile


I = [~ainfall lntensity (100-yr) in incheslhour (from l-D-F curve) 1 4.90 1 5.50 1 5.58 1 5.53 1


Q = CIA


.................... I = Rainfall Intensity in incheslhour (1 0-yr storm) 3.50 inlhr




* The drainage area Is reduced by 25% of the medium density and medium to low density residential areas to account for retention occuring

within walled back yards. This reduced drainage area is used when calculating the weighted m o f f coefficient,









area # (acres) I Sub- I Area Description of Land Use Runoff Coefficient (C)

Total 27.5 acres

NA acres (reduced)* Weighted Runoff Coefficient* =


1 = Length of the Longest Flow Path in feet ........................... 1,325 feet

K b ............................... = Watershed Resistance Coefficient** 0.050

S = Watercourse Slope in feettmile ...................................... 13.2 ft/mile



Q = CIA

C = Runoff Coefficient (weighted).. ........................................ 0.77

.................... I = Rainfall Intensity in inchesthour (10-yr storm) 3.50 inlhr


A = Drainage Area* (contributing areas only) in acres ................ 27.5 acres ........................................... QIO = 10-yr Peak Discharge in cfs 74 cfs .......................................... Qloo = 100-yr Peak Discharge in cfs 440 cfs

* The drainage area is reduced by 25% of the medium densify and medium to low density residential areas to account for retention occuring

within walled back yards, This reduced drainage area is used when calculating the weighted runoff coefficient,

as well as fhe peak discharge.

**For the purposes of this study, the watershed resistance coefficient is constant for a// drainage areas.


Concentration Point 27D Quarter Section Map Numbers 27D

Outfall ID




Sub- I Area area # (acres)

Total 26.3

21.3


acres

acres (reduced)* Weighted Runoff Coefficient* =

Sten 2: Determine Time of Concentration (T,)


............................... Kb = Watershed Resistance Coefficiente* 0.050 ...................................... S = Watercourse Slope in feetlmile 13.2 ftlmile



Q = CIA

C = Runoff Coefficient (weighted). ....................................... 0.71

.................... I = Rainfall Intensity in incheslhour (IO-yr storm) 2.70 inlhr


................ A = Drainage Area* (contributing areas only) in acres 21.3 acres ........................................... QIO = IO-yr Peak Discharge in cfs 41 cfs

Q ~ o o = 100-yr Peak Discharge in cfs ................................... . 60 cfs

* The drainage area is reduced by 25% of the medium density and medium to k w density residential areas to account for retentlon occuring




CITY OF MESA DRAINAGE SYSTEM EVALUATION - PHASE ll Rational Method Calculation Sheet Source: Drainage Design Manual for Maricopa County, Arizona

Concentration Point 28A - combined Quarter Section Map Numbers 28A, C, 36A, C, 44A




Sub- area #

Area (acres) Description of Land Use Runoff Coefficient (C)

9

Total acres

acres (reduced)* Weighted Runoff Coefficient* = 124i9

Sten 2: Determine Time of Concentration /T,J


............................... K b = Watershed Resistance Coefficient** 0.050 ...................................... S = Watercourse Slope in feetlmile 13.2 ftlmile



Q = CIA


................... I = Rainfall Intensity in incheslhour (1 0-yr storm). 1 '37 inlhr



........................................ Qioo = 100-yr Peak Discharge in cfs 323 cfs

(selected T, in minutes


within walled back yanls. This reduced drainage area is used when calculating the weighted runoff coefficient,



lS'try 64

2"dtry 7 1

3 % y 74

4'"try

ClTY OF MESA DRAINAGE SYSTEM EVALUATION - PHASE II Rational Method Calculation Sheet Source: Drainage Design Manual for Maricopa County, Arizona

. Concentration Point 29B-combined Quarter Section Map Numbers 298,29D, 378

Outfall ID MH-3133 Drainage Area 0.65 sq miles




Total 413.9 acres

401.4 acres (reduced)* Weighted Runoff Coefficient* = Q,z!2



.............................. K b = Watershed Resistance Coefficient** 0.050 ...................................... S = Watercourse Slope in feetfmile 13.2 Wmile


- I - -

TC - -


Q = CIA


.................... I = Rainfall Intensity in incheslhour (10-yr storm) 1.53 in/hr

= Rainfall Intensity in incheslhour (100-yr storm) ................... 2.29 in/hr

A = Drainage Area* (contributing areas only) in acres ................ 401.4 acres

Qlo = 10-yr Peak Discharge in cfs ........................................... 483 cfs

Qloo = 100-yr Peak Discharge in cfs .......................................... 723 cfs

* The drainage area is reduced by 12.5% of the medium density and medium to low densify residential areas to account for retention occuring



**For the purposes of this study, the watershed resistance coefficient is constant for all drainage areas,


Concentration Point 29D Quarter Section Map Numbers 29D





Commercial

Total 163.5 acres

156.3 acres (reduced)* Weighted Runoff Coefficient* = ai3l

Step 2: Determine Time of Concentration (T,I

L = Length of the Longest Flow Path in feet .......................... 5,200 feet

K b ............................... = Watershed Resistance Coefficient** 0.050

S = Watercourse Slope in feetlmile ...................................... 13.2 ftlmile

Iterative Process to Determine T , and Rainfall Intensity (I)


Q = CIA


.................... I = Rainfall Intensity in incheslhour (10-yr storm) 2.00 inlhr

................... = Rainfall Intensity in incheslhour ( I OO-yr storm) 2.92 inlhr

.............. A = Drainage Area* (contributing areas only) in acres.. 156.3 acres ........................................... QIO = IO-yr Peak Discharge in cfs 245 cfs






CITY OF MESA DRAINAGE SYSTEM EVALUATION - PHASE II Rational Method Calculation Source: Drainage Design Manual for Maricopa County, Arizona

Concentration Point 34A Quarter Section Map Numbers



Total Area

34A, 34C HW-26D-N

0.33 sq miles




1 190.4 Residential - low density 0.55 2 3.0 Commercial 0.80

Total 213.6 acres

166.0 acres (reduced)" Weighted Runoff Coefficient* = a.59

Ster, 2: Determine Time of Concentration (7"-


............................... Kb = Watershed Resistance Coefficient** 0.050 ..................................... S = Watercourse Slope in feetjmile, 13.2 ftlmile

Iterative Process to Determine T, and Rainfall Intensity (1)


Q = CIA

C = Runoff Coefficient (weighted) ........................ .. ............. 0.59




QIO = 10-yr Peak Discharge in cfs ...................................... 17i cfs


* The drainage area is reduced by 25% of the low density residential areas to account for retention occuring

within depressed back yards. This reduced drainage area is used when calculating the weighted runoff coefficient,


**For the purposes of this study, fhe watershed resistance coefficient is consfant for all drainage areas.


Concentration Point 34B(1) Quarter Section Map Numbers 34B



Step 1 : Determine Weighted Runoff Coefficient (C)

area # (acres) I Area I Description of Land Use Runoff Coefficient (C)

1 20.9 Residential - medium density 0.65 2 56.7 Residential - low densitv 0.55

I

Total 81.6 acres

62.2 acres (reduced)* Weighted Runoff Coefficient* = Qs.kzi Step 2: Determine Time of Concentration (T,)


............................... Kb = Watershed Resistance Coefficient*" 0.050 S = Watercourse Slope in feetlmile ...................................... 13.2 Wmile

Iterative Process to Determine T, and Rainfall Intensity (I)


Q = CIA

C = Runoff Coefficient (weighted). ........................................ 0.59



A = Drainage Area* (contributing areas only) in acres... ............. 62.2 acres

Qlo = 10-yr Peak Discharge in cfs ........................................... 85 cfs

........................................ Qioo = 100-yr Peak Discharge in cfs.. 123 cfs

* The drainage area is reduced by 25% of fhe medium density and low densify residential areas to account for retention occuring

within depressed or walled back yards. This reduced drainage area is used when calculating the weighted runoff coefficient,

as well as the peak discharge. **For the ournoses of this studv. the watershed resistance coefficient is constant for all drainacre areas.

GIN OF MESA DRAINAGE SYSTEM EVALUATION - PHASE II Rational Method Calculation Sheet Source: Drainage Design Manual for Maricopa County, Arizona




Total Area

0.07 sq miles



Runoff Coefficie

Total 45.5 acres

38.2 acres (reduced)* Weighted Runoff Coefficient* = QJl



............................... K b = Watershed Resistance Coefficient** 0.050 S = Watercourse Slope in feetimile ...................................... 13.2 Wmile



Q = CIA



.................. = Rainfall Intensity in incheslhour (1 00-yr storm). 3.34 inlhr


.......................................... Qzoo = 100-yr Peak Discharge in cfs 90 cfs




"*For the purposes of this study, the watershed resistance coefficient is constant for all drainage areas.


Concentration Point 358 Quarter Section Map Numbers 35A, B, & C

Outfall ID




Runoff Coefficient

I I I

Total 96.1 acres

87.1 acres (reduced)* Weighted Runoff Coefficient* = a!il



............................... K b = Watershed Resistance Coefficient*" 0,050

S = Watercourse Slope in feetlmile ...................................... 13.2 Wmile


- I

- - -

Tc - -


Q = CIA


................... I = Rainfall Intensity in incheslhour ( I 0-yr storm). 2.00 inlhr


A = Drainage Area* (contributing areas only) in acres.. ............... 87.1 acres ........................................... Q l o = 10-yr Peak Discharge in cfs 89 cfs


" m e drainage area is reduced by 25% of the medium density and medium to low density residential areas to account for retention occuring

wHhin walled back yards. This reduced drainage area is used when calculating the weighted runoff coefficient,

as well as the peak discharge. **For the purposes of this study, the watershed resistance coefficient is constant for all drainage areas.

ClTY OF MESA DRAINAGE SYSTEM EVALUATION - PHASE I1 Rational Method Calculation Sheet Source: Drainage Design Manual for Maricopa County, Arizona




Total Area

36A (I) 36A

MH3558 0.05

0.00 0.05

sq miles sq miles sq miles


area S u b # I (acres) Area I Description of Land Use Runoff Coefficient (C)

Total 33.7 acres



7, = 11.4 L 0 . 5 ~ ~ 0.52 ~ 4 . 3 1 /-0.38


............................. K b = Watershed Resistance Coefficientx*.. 0.050 ...................................... S = Watercourse Slope in feetlmile 13.2 Wmile



Q = CIA


.................... I = Rainfall Intensity in inchedhour (10-yr storm) 2.20 in/hr

= Rainfall Intensity in inches/hour (1 00-yr storm). .................. 3.30 inlhr

A = Drainage Area* (contributing areas only) in acres ................ 29.7 acres ........................................... Qio = 10-yr Peak Discharge in cfs 49 cfs


* The drainage area is reduced by 25% of the medium density and medium to low density residential areas to account for retenfion occuring


-.xn. 4 as well as fhe peak discharge.

**For the purposes of this study, the watershed resistance coefficient is constant for aN drainage areas.

CITY OF MESA DRAINAGE SYSTEM EVALUATION - PHASE li Rational Method Calculation Sheet Source: Drainage Design Manual for Maricopa County, Arizona

Concentration Point 36A (2) Quarter Section Map Numbers 36A

Outfall ID MH3558




area Sub- # I (acres) Area I Description of Land Use Runoff Coefficient (C)

Commercial

I - - - - .-

9 1 Total

73.9 acres

57.9 acres (reduced)* Weighted Runoff Coefficient* = lLfia


T, = 11.4 ~ 0 . 5 ~ ~ 0 . 5 2 S-0.31 j-0.38


............................... K b = Watershed Resistance Coefficient*" 0.050 S = Watercourse Slope in feetfmile ...................................... 13.2 Wmile

Iterative Process to Determine 7, and Rainfall Intensity (I)


Q = CIA



................. = Rainfall Intensity in incheslhour (1 00-yr storm).. 3.94 inlhr

A = Drainage Area* (contributing areas only) in acres... ............. 57.9 acres ........................................... Qlo = IO-yr Peak Discharge in cfs 104 cfs

........................................ Qioo = 100-yr Peak Discharge in cfs.. 154 cfs

* The drainage area is reduced by 25% of the medium density and medium to low densify residential areas to account for retention occurlng





Concentration Point 36B

Quarter Section Map Numbers 36B Outfall ID MH-3060




Runoff Coefficient

I

Total 241.8 acres

206.7 acres (reduced)" Weighted Runoff Coefficient* = Q&z Step 2: Determine Time of Concentration (T,)


............................... K b = Watershed Resistance Coefficient*" 0.050


Iterative Proces ; to Determine T, and Rainfall lntensity (I)

Selected Tc in minutes

Rainfall Intensity (100-yr) in incheslhour (from I-D-F curve) Adjusted Intensity in incheslhour Time of Concentration in minutes


Q = CIA


................... I = Rainfall Intensity in incheslhour (1 0-yr storm). 1.95 inlhr

.................. = Rainfall Intensity in incheslhour (1 00-yr storm). 2.90 inlhr

A = Drainage Area* (contributing areas only) in acres ................ 206.7 acres ........................................... QIO = 10-yr Peak Discharge in cfs 271 cfs

Q ~ o o = IOO-yr Peak Discharge in cfs .......................................... 403 cfs

* The drainage area is reduced by 25% of fhe medium density and medium to low density residential areas to account for retention occuring


as well as the peak discharge. i


CITY OF MESA DRAINAGE SYSTEM EVALUATION - PHASE I I Rational Method Calculation Sheet Source: Drainage Design Manual for Maricopa County, Arizona

Concentration Point 378 Quarter Section Map Numbers 37B





Total 85.9 acres

82.3 acres (reduced)* Weighted Runoff Coefficient* = QJXl


T, = 11.4 ~ 0 . 5 ~ ~ 0 . 5 2 S-0.31 i-0.38


.............................. K b = Watershed Resistance Coefficient** 0.050 ...................................... S = Watercourse Slope in feetimile 13.2 ft/mile

Iterative Process to Determine 7°C and Rainfall Intensity (I)


Q = CIA

C = Runoff Coefficient (weighted) ....................................... 0.80

.................... I

= Rainfall Intensity in incheslhour (1 0-yr storm) 2.43

= Rainfall Intensity in incheslhour (1 00-yr storm). .................. 3.63

A = Drainage Area* (contributing areas only) in acres ................ 82.3 ........................................... QIO = 10-yr Peak Discharge in cfs 159 .......................................... Qioo = 100-yr Peak Discharge in cfs 238

inlhr

inlhr

acres cfs

cfs

* The drainage area is reduced by 12.5% of the medium density and medium to low density residential areas to account for retention occuring





Concentration Point 42A Quarter Section Map Numbers 42A, 42C (west of canal)

Outfall ID HW-26D-N Drainage Area 0.09 sq miles

Areas with 100% Retention 0.1 1 sq miles Total Area 0.20 sq miles


area # (acres) I Sub- I Area Description of Land Use Runoff Coefficient (C)

Total 55.4 acres


Ster, 2: Determine Time of Concentration (T,)


............................... K b = Watershed Resistance Coefficient*" 0.050 ...................................... S = Watercourse Slope in feettmile 13.2 Wmile

Iterative Process to Determine T, and Rainfall Intensity (1)


C = Runoff Coefficient (weighted) ........................................ 0.67

.................... I = Rainfall Intensity in inchesthour (IO-yr storm) 2.20 inthr

= Rainfall Intensity in inchesthour ( I OO-yr storm). .................. 3.30 inthr


Qio = 10-yr Peak Discharge in cfs ........................................... 68 cfs

.......................................... Q~oo = 100-yr Peak Discharge in cfs 102 cfs



-.-XI









Total 3.4 acres

NA acres (reduced)* Weighted Runoff Coefficient* = 1283.


L = Length of the Longest Flow Path in feet ........................... ............................... K b = Watershed Resistance Coefficient*"

...................................... S = Watercourse Slope in feetlmile

1,150 feet

0.050

13.2 ftlmile


- I

- - -

T", - -


Q = CIA

C = Runoff Coefficient (weighted).. ........................................ 0.83



A = Drainage Area* (contributing areas only) in acres ................ 3.4 acres ......................................... QIO = 10-yr Peak Discharge in cfs.. 10 cfs

Qioo = 100-yr Peak Discharge in cfs.. ...................................... 15 cfs

* m e drainage area is reduced by 25% of the medium density and medium to low density residential areas to account for retention occuring


_IX



C l N OF MESA DRAINAGE SYSTEM EVALUATION - PHASE I 1 Rational Method Calculation Sheet Source: Drainage Design Manual for Maricopa County, Arizona


Outfall ID NA Drainage Area

Areas with 100% Retention 0.02 sq miles 0.20 sq miles




Total 11.5 acres




............................... Kb = Watershed Resistance Coefficient** 0.050 S = Watercourse Slope in feettmile ..................... ..... ........ 13.2 Wmile


step 3: Calculate Peak Discharge (Q)

Q = CIA

.......................................... C = Runoff Coefficient (weighted) 0.82 .................... I = Rainfall Intensity in incheslhour (10-yr storm) 2.05 inlhr

= Rainfall Intensity in incheslhour (1 00-yr storm) ................... 2.94 inlhr

A = Drainage Area* (contributing areas only) in acres... ............. 11.5 acres Qlo = 10-yr Peak Discharge in cfs ........................................... 19 cfs



within walled back yards, This reduced drainage area is used when calculating the weighted runoff coefficient,



CITY OF MESA DRAINAGE SYSTEM EVALUATION = PHASE II Rational Method Calculation Sheet Source: Drainage Design Manual for Maricopa County, Arizona



Areas with 100% Retention 0.97 sq miles Total Area 1 .OO sq miles


area # I (acres) Area I Description of Land Use Runoff Coefficient (C)

Total 20.0 acres




............................... K b = Watershed Resistance Coefficient** 0.050 ................................... S = Watercourse Slope in feetlmile,.. 13.2 Wmile


- - I - -

Tc - -


Q = CIA




A = Drainage Area* (contributing areas only) in acres ................ 20.0 acres ......................................... (210 = 10-yr Peak Discharge in cfs.. 33 cfs

QIOO = 100-yr Peak Discharge in cfs .......................................... 49 cfs



as we// as fhe peak discharge.


CITY OF MESA DRAINAGE SYSTEM EVALUATION = PHASE I1 Rational Method Calculation Sheet Source: Drainage Design Manual for Maricopa County, Arizona

Concentration Point 44A Quarter Section Map Numbers 44A, 36C

Outfall ID MHI 1205




area Sub- # I (acres) ,Irea I Description of Land Use Runoff Coefficient (C} I

Total 26.8 acres

22.5 acres (reduced)* Weighted Runoff Coefficient* = Q4.m

Ster, 2: Determine Time of Concentration (7,)


............................. K b = Watershed Resistance Coefficient**. 0.050


Iterative Process to Determine Tc and Rainfall lntensity (I}


Q = CIA


................... I = Rainfall Intensity in incheslhour (1 0-yr storm). 3.85 inlhr

= Rainfall Intensity in incheslhour (1 00-yr storm) ................... 5.65 inlhr

A = Drainage Area* (contributing areas only) in acres ................ 22.5 acres ........................................... Q l o = 10-yr Peak Discharge in cfs 60 cfs





**For the purposes of this study, the watershed resistance coefficient is constant for a# drainage areas.

CITY OF MESA DRAINAGE SYSTEM EVALUATION - PHASE 11 Rational Method Calculation Sheet Source: Drainage Design Manual for Maricopa County, Arizona

Concentration Point 44B Quarter Section Map Numbers 44A, 44B, 44D

Outfall ID MH2908




Sub- area # (acres) Area I Description of Land Use Runoff Coefficient (C)

Total 206.8 acres

172.3 acres (reduced)* Weighted Runoff Coefficient* = Qsfa



............................... K b = Watershed Resistance Coefficientx* 0.050 ...................................... S = Watercourse Slope in feet/mile 13.2 ftlmile

iterative Process to Determine Tc and Rainfall lntensity (I)

- I

- - -

T c - -


Q = CIA


.................. 1 = Rainfall Intensity in incheslhour (1 0-yr storm).. 2.23 inlhr



........................................ Qioo = 100-yr Peak Discharge in cfs 390 cfs

* The drainage area is reduced by 25% of the medium density and medium to k w density residential areas fo account for retention occuring


as we// as the peak discharge.


CITY OF MESA DRAINAGE SYSTEM EVALUATION - PHASE 11 Rational Method Calculation Sheet Source: Drainage Design Manual for Maricopa County, Arizona




Total Area

458 45B, 45D

MH2753 0.46 sq miles 0.00 sq miles 0.46 sq miles


1 9 1 13.1 1 ROW 110 ft 1 0.82 I Total 291.9 acres

245.6 acres (reduced)" Weighted Runoff Coefficient* = QzS!



Kb = Watershed Resistance Coefficient** .................. ..,. ....... 0.050

S = Watercourse Slope in feetfmile ...................................... 13.2 ft/mile

Iterative Process to Determine T, and Rainfall Intensity ( I )


Q = CIA




A = Drainage Area* (contributing areas only) in acres ................ 245.6 acres ........................................... Q ~ Q = 10-yr Peak Discharge in cfs 300 cfs

....................................... Qioo = 100-yr Peak Discharge in cfs 446 cfs


within walled back yards. This reduced drainage area is used when calculating the weighted runoff coefficient, .


**For the purposes of fhis study, the watershed resistance coefficient is constant for all drainage areas.

CITY OF MESA DRAINAGE SYSTEM EVALUATION = PHASE 11 Rational Method Calculation Sheet Source: Drainage Design Manual for Maricopa County, Arizona

Concentration Point 51 B Quarter Section Map Numbers 51A, 51B, 51C, 51D, 59B

Outfall ID MCK-16881





Total 344.8 acres



7, = 11.4 L o . 5 ~ b o . 5 2 S ~ . 3 1 i-0.38


K b = Watershed Resistance Coefficient** ............................... 0.050



- I

- - -

T c - -


Q = CIA

C = Runoff Coefficient (weighted).. ....................................... 0.64




.......................................... Qmo = 100-yr Peak Discharge in cfs 456 cfs

* The drainage area is reduced by 25% of the medium density and medium to low density residential areas to account for retention occun'ng

within walled back yards. This reduced drainage area is used when calculafing the weighfed runoff coefficient,

as well as the peak discharge. **For the purposes of this study, the watershed resistance coefficient is constant for ail drainage areas.



Outfall ID

Drainage Area Areas with 100% Retention

Total Area

52D 52D

MH-2628 .0.18 sq miles 0.06 sq miles 0.24 sq miles


Description of Land Use Runoff Coefficient (C) I

Total 112.6 acres

90.6 acres (reduced)* Weighted Runoff Coefficient* = QBi

Steo 2: Determine Time of Concentration (T,)


............................... K b = Watershed Resistance Coefficient** 0.050 ...................................... S = Watercourse Slope in feetlmile 13.2 ftlmile

Iterative Process to Determine T, and Rainfall lntensity (1)


Q = CIA

......................................... C = Runoff Coefficient (weighted). 0.69

................... I = Rainfall Intensity in incheslhour ( I 0-yr storm). 2.1 5

................... = Rainfall Intensity in incheslhour (100-yr storm) 3.16

................ A = Drainage Area* (contributing areas only) in acres 90.6

Qlo = 10-yr Peak Discharge in cfs ........................................... 135 ........................................ Qioo = 100-yr Peak Discharge in cfs.. 198

inlhr

inlhr

acres

cfs

c fs

* The drainage area is reduced by 25% of the medium densify and medium to low density resldentlal areas to account for retention occuring



**For the purposes of this study, fhe watershed resistance coefficient is constant for all drainage areas.

CITY OF MESA DRAINAGE SYSTEM EVALUATION - PHASE ll Rational Method Calculation Sheet Source: Drainage Design Manual for Maricopa County, Arizona

Concentration Point

Quarter Section Map Numbers 53B, 53D Outfall ID MH2685





Total 151.4 acres

1 18.2 acres (reduced)" Weighted Runoff Coefficient* = QLiB



K b .............................. = Watershed Resistance Coefficient**. 0.050



- I

- - -

T C - -


Q.= CIA


.................... I = Rainfall Intensity in incheslhour (1 0-yr storm) 2.37 inlhr




* The drainage area is reduced by 25% of the medium density and medium to /ow density residential areas to account for retention occudng

within walled back yads. This reduced drainage area is used when calculating the weighted runoff coefficient,



C I N OF MESA DRAINAGE SYSTEM EVALUATION - PHASE II Rational Method Calculation Sheet Source: Drainage Design Manual for Maricopa County, Arizona




Total Area

60B 60B

MH-2197 0.1 1 sq miles



Sub- area # (acres) Area I Description of Land Use Runoff Coefficient (C)

-- -

ROW 110ft

Total 68.63 acres

56.7 acres (reduced)* Weighted Runoff Coefficient* = QLl



............................... Kb = Watershed Resistance Coefficient** 0.050 S = Watercourse Slope in feetlmile ...................................... 13.2 ftlmile


- I

- - -

Tc - -


Q = CIA

Runoff Coefficient (weighted). ......................................... 0.71

.................... Rainfall Intensity in incheslhour (1 0-yr storm) 1.95 inlhr

................... Rainfall Intensity in incheslhour (100-yr storm) 2.90 inlhr

................ Drainage Area* (contributing areas only) in acres 56.7 acres ........................................... IO-yr Peak Discharge in cfs 79 cfs

.......................................... 1 OO-yr Peak Discharge in cfs 117 cfs


withln walled back yards. This reduced drainage area is used when calculating the weighted ~ n o f f coefficient, as well as the peak discharge.

**For the purposes of this study, the watershed resistance coefficient Is constant for all drainage areas.



Outfall ID MH-2205





Commercial

Total 204.2 acres

NA acres (reduced)" Weighted Runoff Coefficient* = Qtix!



............................... K b = Watershed Resistance Coefficient** 0.050 ...................................... S = Watercourse Slope in feetlmile 13.2 Wmile


- I

- = Adjusted Intensity in incheslhour 2.70 2.73 2.72

TC = Time of Concentration in minutes 49.22 49.03 1 49.09


Q = CIA

C = Runoff Coefficient (weighted) ........................................ 0.79

.................... I = Rainfall Intensity in incheslhour (IO-yr storm) I .80 inlhr

................... = Rainfall Intensity in incheslhour (IOO-yr storm) 2.72 inlhr




within walled back yards. This reduced drainage area is used when calculating the weighted runoff coefficient, r'

---+ as well as the peak discharge.








ROW I lOf t

Total 32.32 acres

24.7 acres (reduced)* Weighted Runoff Coefficient* = Q2iz


.......................... L = Length of the Longest Flow Path in feet 2,350 feet

............................... K b = Watershed Resistance Coefficient** 0.050 S = Watercourse Slope in feetlmile ...................................... 13.2 ftlmile

Iterative Process to Determine 7, and Rainfall Intensity (I)

- - I - -

Tc - -


Q = CIA

C = Runoff Coefficient (weighted).. ..................................... 0.57 ...................

I = Rainfall Intensity in incheslhour (1 0-yr storm). 2.75 inlhr


A = Drainage Area* (contributing areas only) in acres ................ 24.7 acres ........................................... Q f o = 10-yr Peak Discharge in cfs 39 cfs .......................................... Qioo = 100-yr Peak Discharge in cfs 59 cfs

* The drainage area is reduced by 25% of the medium density and medium to low densify residential areas to account for retention occurlng




EVALUATION - PHASE I1

Maricopa County, Arizona




Step I: Determine Weighted Runoff Coefficient (6)


Total 4.5 acres NA acres (reduced)* Weighted Runoff Coefficient* =



............................... Kb = Watershed Resistance Coefficient** 0.050 ...................................... S = Watercourse Slope in feetlmile 13.2 Wmile


- I

- - -

Tc - -


Q = CIA

C = Runoff Coefficient (weighted) ........................................ 0.82 .................... I = Rainfall Intensity in incheslhour (10-yr storm) 2.90 inlhr



Qlo = 10-yr Peak Discharge in cfs ........................... .. . . . . 11 cfs

.......................................... QIOO = 100-yr Peak Discharge in cfs 1

* The drainage area is reduced by 25% of the medium density and medium to low density residential areas to account for retention occuting

within walled back yards. This reduced drainage area is used when calculating the weighted runoff coeMcient,

as well as the peak dischame. d

WFor fhe purposes of this study, the watershed resistance coefficient is constant for all drainage areas.

C l N OF MESA DRAINAGE SYSTEM NALUATIO Rational Method Calculation Sheet Source: Drainage Design Manual for Maricopa County, Arizona




638 MH-550-S



Total 5.8 acres

NA acres (reducedy Weighted Runoff Coefficient* =


rc = 11.4 ~ 0 . 5 Kbo.52s4.3i j0.38


............................... K b = Watershed Resistance Coefficient** 0.050 S = Watercourse Slope in feevrnile ...................................... 13.2 ftlmile

Iterative Process to Determine T, and Rainfall intensity (I)

Q = CIA

C = Runoff Coefficient (weighted) ......................................... 0.82 .................... I = Rainfall Intensity in incheslhour (10-yr storm) 2.75 inlhr

= Rainfall Intensity in incheslhour ( I 00-yr storm). .................. 4.19 inlhr

A = Drainage Area* (contributing areas only) in acres ................ 5.8 acres ........................................... Qio = 10-yr Peak Discharge in cfs 13 cfs

Q i o o = 100-yr Peak Discharge in cfs ......................................... 20 cfs

* The drainage area is reduced by 25% of the medium density and medium to low density residentfa1 areas to account for retention occurfng

within walled back yards. This reduced drainage area is used when calculafing the weighted runoff coefficient,

as well as the peak discharge. -+--" *For the purposes of this study, the ~ f e r s h e d resistance coefficient is constant for all drainage areas.

YSTEM EVALUATI Rational Method Calculation Sheet Source: Drainage Design Manual for Maricopa County, Arizona

Concentration Point 66B Quarter Section Map Numbers 65B,66A, B, D





Total 25.1 acres


Step 2: Determine Time of Concentration v,)


K b = Watershed Resistance Coefficient** ............................... 0.050 S = Watercourse Slope in feetfmile ...................................... 13.2 ftlmile

Iterative Process to Determine T, and Rainfall lntensity ( I )


Q = CIA

C = Runoff Coefficient (weighted) .......................................... 0.82 .................... I = Rainfall Intensity in incheslhour (10-yr storm) 1.56 inlhr .................. = Rainfall Intensity in incheslhour (100-yr storm). 2.34 inlhr

A = Drainage Area* (contributing areas only) in acres .........,...... 25.1 acres ........................................... Q t o = 10-yr Peak Discharge in cfs 32 cfs .......................................... Qioo = 100-yr Peak Discharge in cfs 48 cfs

* The drainage area is reduced by 25% of the medlum density and medium to low densify resldentlal areas to account for retention occudng

wlthin walled back yards. This reduced drainage area is used when calculating the weighfed runoff coefflclent,

as well as the peak dlscharge. i-

I__-

*For fhe purposes of this study, the watershed resistance coefficient Is constant for all drainage areas.

INAGE SYSTEM EVALUATION - PHASE 11 Rational Method Calculation Sheet Source: Drainage Design Manual for Maricopa County, Arizona


Outfall ID Drainage Area '


68A 68A, 68C MH-2068




Total 7.6 acres

NA acres (reduced)* Weighted Runoff Coefficient* = Q.83


Tc = 11.4 ~ 0 . 5 ~ ~ 0 . 6 2 ~ - 0 . 3 f i-0,38


............................... K b = Watershed Resistance Coefficient** 0.050 ...................................... S . = Watercourse Slope in feetlmile 13.2 Wmile

iterative Process to Determine T, and Rainfall lntensity (I)

I = 1 ~ainfall Intensity (1 00yr) in incheslhour (fmm I-0-F curve) 1 3.08 1 3.12 1 1

Step 3: Calculate Peak Discharge (Qf

Q = CIA

C = Runoff Coefficient (weighted).. ....................................... 0.83 .................... I = Rainfall Intensity in incheslhour (10-yr storm) 2.05 inlhr

= Rainfall Intensity in incheslhour (I 00-yr storm). .................. 2.94 inlhr

A = Drainage Area* (contributing areas only) in acres ................ 7.6 acres ......................................... Qlo = 10-yr Peak Discharge in cfs.. 13 cfs


* The drainage area is reduced by 25% of the medlum density and medium to low density residential areas to account for retention occuring within walled back yards. This reduced drainage area is used when caiculating the weighted runoff coemcient,

as well as the peak discharge. WFor the purposes of this study, the watershed resistance coefficient is constant for all drainage ateas.

CITY OF MESA DRAINAGE SYSTEM EVALUATION - PH Rational Method Calculation Sheet Source: Drainage Design Manual for Maricopa County, Arizona




73B 73A, B, D MH-1373


Step q: Determine weighted Runoff CoefFicient (C)


Total 14.0 acres

NA acres (reducedr Weighted Runoff Coefficient* =


L = Length of the Longest Flow Path in feet ........................... 4,700 feet .............................. K b = Watershed Resistance Coefficient**. 0.050



Q = CIA

C = Runoff Coefficient (weighted) ....................................... 0.83

.................... I = Rainfall Intensity in incheslhour (10-yr storm) 1.75 in/hr

= Rainfall Intensity in incheslhour ( I 00-yr storm) ................... 2.59 inlhr

A = Drainage Area* (contributing areas only) in acres ................ 14.0 acres ........................................... Qlo = 10-yr Peak Discharge in cfs 20 cfs .......................................... Qioo = 100-yr Peak Discharge in cfs 30 cfs

* The drainage area is reduced by 25% of the medium density and medium to low density residenfial areas to account for retention occurlng


as well as the peak dischatge. *For the purposes of this study, the watershed resistance coefficient is constant for aN drainage areas.

CITY OF MESA DRAINAGE SYSTEM EVALUATION PHASE li Rational Method Calculation Sheet Source: Drainage Design Manual for Maricopa County, Arizona

Concentration Point Quarter Section Map Numbers 76B



1

~escr i~ t ion of Land Use Runoff Coefficient (C)

6.5 acres

NA acres (reduced)" Weighted Runoff Coefficient* = a

Stea 2: Determine Time of Concentration (TJ

L = Length of the Longest Flow Path in feet ........................... 3,750 feet ............................... K b = Watershed Resistance Coefficiente* 0.050



- I

- - -

7°C - -


Q = CIA

C = Runoff Coefficient (weighted).. ........................................ 0.82 ................... I = Rainfall Intensity in incheslhour (1 0-yr storm). 2.33 inlhr

................... = Rainfall Intensity in incheskour (100-yr storm) 3.49 inlhr


Qfo = 10-yr Peak Discharge in cfs ................... .... .............. 12 cfs


* Tlte drainage area is reduced by 25% of the medium density and medium to low density residentral areas to account for retention occuring


as well as the peak discharge. **For the purposes of fhis study, the watershed resistance coefficient is constant for all drainage areas.

C l N OF MESA DRAINAGE SYSTEM EVALUATION - PHASE I1 Rational Method Calculation Sheet Source: Drainage Design Manual for aricopa County, Arizona

Concentration Point 77B Quarter Section Map Numbers 77B, 77D, 85B

Outfall ID MH-I 502 Drainage Area 0.52 sq miles



Total 332.2 acres

NA acres (reduced)* Weighted Runoff Coefficient* = QJ3Q

Step 2: Determine Time of Concentration (TJ

T, = 17.4 LO.5 Kbo.62Sa.3f j-0.38


.............................. Kb = Watershed Resistance Coefficiente*. 0.050 ...................................... S = Watercourse Slope in feetlmile 13.2 fttmile

Iterative Process to Determine 1, and Rainfall lntensity (I)

- - I - - 7, - -


Q = CIA

C = Runoff Coefficient (weighted) ........................................ 0.80 .................... I = Rainfall Intensity in incheslhour (10-yr storm) 1.70 inlhr

= Rainfall Intensity in incheslhour (1 00-yr storm).. ................. 2.52 inlhr

................ A = Drainage Area* (contributing areas only) in acres 332.2 acres QIO = 10-yr Peak Discharge in cfs ........................................... 453 cfs

Qioo = 100-yr Peak Discharge in cfs ......................................... 671 cfs

* The drainage area is reduced by 25% of the medium density and medium to low density residential areas to account for retention occutfng

wifhin walled back yards. This reduced drainage area is used when calculating the weighted wnoff coefficient,

as weii as the peak discharge. **For fhe purposes of fhis study, the wafershed resistance coefficient Is constant lor all drainage areas.

C l N OF MESA DRAINAGE SYSTEM EVALUATIO Rational Method Calculation Sheet Source: Drainage Design Manual for Maricopa County, Arizona

Concentration Point 838 Quarter Section Map Numbers 83A, 8, C, D


Areas 'with 100% Retention 0.98 sq miles Total Area 1.00 sq miles



Total 15.8 acres

NA acres (reduced)* Weighted Runoff Coefficient* = i2.B

Step 2: Determine Time of Concentration (7,) i

Tc = I f ;# ~ 0 . 5 ~ ~ o . 5 2 ~ " 3 1 / & 3 8

L = Length of the Longest Flow Path in feet ........................... 5,280 feet ............................... K b = Watershed Resistance Coefficiente* 0.050

S = Watercourse Slope in feetlmile ...................................... 20 Wmile

Iterative Process to Determine 7°C and Rainfall lntensity (I)

- I

- - -

Tc - -

Step 3: Cdculate Peak Discharge (Q)

Q = CIA

.......................................... C = Runoff Coefficient (weighted) 0.83 .................... I = Rainfall Intensity in inchesthour (1 0-yr storm) 2.20 inlhr


A = Drainage Area* (contributing areas only) in acres ................ 15.8 acres ........................................... Qlo = 10-yr Peak Discharge in cfs 29 cfs .......................................... Q~oo = 100-yr Peak Discharge in cfs 43 cfs

* The drainage area is reduced by 25% of the medium density and medium to low density residentla/ areas to account for retention occuring

within walled back yards. mis reduced drainage area is used when calculating the weighted runoff coeflcienf,


**For the purposes of this study, the watershed resistance coeflcient is constant for all drainage areas.

G I N OF MESA DRAINAGE SYSTEM WALUATION - PHASE I1 Rational Method Calculation Sheet Source: Drainage Design Manual for Maricopa County, Arizona


Outfall ID MH-I 793 Drainage Area 0.01 sq miles




Total 7.9 acres. NA, acres (reduced)* Weighted Runoff Coefficient* = QJu

S t e ~ 2: Determine Time of Concentration (T,)

L = Length of the Longest Flow Path in feet ........................... 5,280 feet ............................ K b = Watershed Resistance Coefficient*",.. 0.050

.................................... S = Watercourse Slope in feetlmile.. 49. I Wmile



Q = CIA


.................... I = Rainfall Intensity in incheslhour (10-yr storm) 2.75

= Rainfall Intensity in incheslhour (100-yr storm) ................... 4.19

A = Drainage Area* (contributing areas only) in acres ................ 7.9 ........................................... Qlo = 10-yr Peak Discharge in cfs I 8 .......................................... Qloo = 100-yr Peak Discharge in cfs 28

inkr

inlhr

acres cfs

cfs

* The drainage area is reduced by 25% of the medium densify and medium to low densify residential areas to account for retention occuring within walled back yards. This reduced drainage area is used when calculating the weighted runoff coefficient,


*For the purposes of this study, the watershed resistance coefficient Is constant for all drainage areas.

GIN OF MESA DRAINAGE SYSTEM Rational Method Calculation Sheet Source: Drainage esign Manual for Maricopa County, Arizona

Concentration Point 89B Quarter Section Map Numbers 89B, 89D

Outfall ID NA Drainage Area 0.02 sq miles



- Sub-

area #

1 2 - 3 4 - 6 7 - 8 - 9

(acres) Area I Description of Land Use Runoff CoefficientfC)

Total 13.3 acres

NA acres (reduced)* Weighted Runoff Coefficient* = - 0.82

Stea 2: Determine Time of Concentration (T,)

L = Length of the Longest Flow Path in feet.., ........................ 5,280 feet ............................... Kb = Watershed Resistance Coefficient** 0.050

...................................... S = Watercourse Slope in feetlmile 79.2 Wmile


- I -

T c -


Q = CIA

C = Runoff Coefficient (weighted) .......................................... 0.82 .................... I

= Rainfall Intensity in incheskour (10-yr storm) 3.15 inlhr = Rainfall Intensity in incheslhour (100-yr storm) ................... 4.71 inihr

A = Drainage Area* (contributing areas only) in acres, ............... 13.3 acres Q.ro = 10-yr Peak Disdharge in cfs ........................................... 34 cfs

QIOO = 100-yr Peak Discharge in cfs .......................................... 51 cfs 3



as web as the peak discharge. *For the purposes of this study, the watershed resistance coefficient is constant for all drainage areas.


Concentration Point 89B - combined Quarter Section Map Numbers 89B1 89D1 97B


Areas with 100% Retention 0.70 sq miles Total Area 0.74 sq miies



Total 25.0 acres

NA acres (reduced)". Weighted Runoff Coefficient*. =

' Step 2: Determine Time of Concentration fl,)


............................... K b = Watershed Resistance Coefficient** 0.050 ...................................... S = Watercourse Slope in feetlmile 79.2 ft/mile

Iterative Process to ~eterrnine Tc and Rainfall Intensity (I)

Step 3: Calculate Peak Discharge (Q) 4

Q = CIA

C = Runoff Coefficient (weighted) ......................................... 0.82 ...................

I = Rainfall Intensity in incheslhour ( I 0-yr storm). 2.67 inlhr


A = Drainage Area* (contributing areas only) in acres ................ 25.0 acres ........................................... Q l o = 10-yr Peak Discharge in cfs 55 cfs

Qzoo = 100-yr Peak Discharge in cfs ....................................... 81 cfs

* 7he drainage area is reduced by 25% of fhe medlurn density and medium to low densly residential areas to account for retention occuring

wifhin walled back yards. Thls reduced drainage area is used when calculating fhe welghted runoff coefficient,

as well as the peak discharge. **For the purposes of this study, the watershed resistance coefflclent is constant for all drainage areas.

GIN OF MESA DRAINAGE SYSTEM EVALUATI Rational Method Calculation Sheet Source: Drainage Design Manual for Maricopa County, Arizona


Outfail ID Drainage Area


91 B 91A, B, C, D

MH-1186 0.36 sq miles 0.64 sq miles I .OO sq miles

Step I: Determine Weighted Runoff Coefficient (C) 3


Total 230.1 acres

175.1 acres* (reduced)*' Weighted Runoff Coefficient* = QJS


T, = 7 7.4 L 0 . 5 ~ ~ 0 . 5 2 ~ - 0 . 3 1 i4.38

L = Length of the Longest Flow Path in feet ........................... 6,000 feet .............................. Kb = Watershed Resistance Coefficient*". 0.050

S = Watercourse Slope in feetlmile ...................................... 64.1 Wmiie


Step 3: Calculate Peak Discharge (€2)

Q = CIA

C = Runoff Coefficient (weighted) .......................................... 0.63 .................... I = Rainfall Intensity in incheslhour (10-yr storm) 2.80 inthr

................... = Rainfall Intensity in incheskour (1 00-yr stom) 4.21 inlhr ............. A = Drainage Area* (contributing areas only) in acres... 175.1 acres

........................................... Qlo = 10-yr Peak Discharge in cfs 309 cfs Q ~ o o = 100-yr Peak Discharge in ds .......................................... 464 cfs

I

I * The drainage area b reduced by 25% of the medium density and medium to low densify residential areas tt5 account for retention occuring

within walled back yarrls. This reduced drainage area is used when calculating the weighted runoff coeftlcient,

as well as the peak discharge. 1 Y **For the purposes of this study, the watershed resistance coefficient is constant for all drainage areas.

t

ITY OF MESA DRAINAGE SYSTEM EVALUATIO ational Method Calculation Sheet

Source: Drainage Design Manual for Maricopa County, Arizona

Concentration Point 978 Quarter Section Map Numbers 978

Outfall ID NA Drainage Area 0.004 sq miles



Total 2.7 acres NA acres (reduced)" Weighted Runoff Coefficient* =


........................... L = .Length of the Longest Flow Path in feet 900 feet

Kb = Watershed Resistance Coefficient*+ ............................... 0.050 ................................. S = Watercourse Slope in feetlmile.,. 79.2 Wmile


- I

- - -

T C - -

Q = CIA

.......................................... C = Runoff Coefficient (weighted) 0.83 .................... . I = Rainfall Intensity in incheskour (1 0-yr storm) 5.50 inihr


A = Drainage Area* (contributing areas only) in acres ................ 2.7 acres ........................................... Qlo = 10-yr Peak Discharge in cfs 12 cfs .......................................... Q ~ o o = 100-yr Peak Discharge in cfs 18 cfs

4

r

* The drainage area Is reduced by 25% of the medium density and medium to low density residential areas to account for retentlon occuring within walled back yards, This reduced drainage area is used when calculating the weighted runoff coefficient, as well as the peak discharge. "For the purposes of this study, the watershed resistance coefticient is constant for all drainage areas.

EVALUATION - PHASE II

Source: Drainage Design Manual for Maricopa County, Arizona


Outfall ID Drainage Area sq miles

Areas with 100% Retention sq miles Total Area sq miles



Total 15.8 acres

NA acres (reducedy Weighted Runoff Coefficient* =

Step 2: Determine Time of Concentration (7,) 1

7, = 7 7.4 ~ 0 . 5 K~ 0.52 ~ - 0 . 3 1 i-0.38


Kb = Watershed Resistance Coefficient*" ............................... 0.050 S = Watercourse Slope in feetlmile .................................... 79.2 ft/mile


- 1

- - -

Tc - -


Q = CIA

C = Runoff Coefficient (weighted).. ....................................... 0.83

................... I = Rainfall Intensity in incheslhour (1 0-yr storm). 3.1 5 inlhr

= Rainfall Intensity in incheslhour (100-yr storm) ................... 4.71 in/hr



* 7he drainage area Is reduced by 25% of the medium density and medium to low densify residential areas to account for retention occuting within walled back yards. This reduced drainage area Is used when calculating the weighted runoff coefficient,

as well as the peak discharge. *For the purposes of this study, the watershed resistance coefficient is constant for all drainage areas.

Rational Method Calculation Sheet Source: Drainage Design Manual for Maricopa County, Arizona

Concentration Point 99B Quarter Section Map Numbers 99A, B, C

Outfail ID Drainage Area 0.04 sq miles




Total 27.7 acres



L = Length of the Longest Flow Path in feet .................... : ...... 9,300 feet

............................... Kb = Watershed Resistance Coefficient** 0.050 ...................................... S = Watercourse Slope in feet/mile 79.2 ft/mile


- I

- - -

T c - -


Q = CIA

C = Runoff Coefficient (weighted). ........................................ 0.83


= Rainfall Intensity in incheslhour ( I 00-yr storm). .................. 3.82 inlhr

A = Drainage Area* (contributing areas only) in acres ......... ..; .... 27.7 acres ........................................... Qlo = 10-yr Peak Discharge in cfs 58 cfs

Qjoo = 100-yr Peak Discharge in cfs .......................................... 88 cfs

* The drainage area is reduced by 25% of the medium density and medlum to low density residentlal areas to account for retention occuring

within walled back yards. This reduced drainage area is used when calculating the weighted runoff coefncient, as well as fhe peak discharge. **For the purposes of this study, the watershed resistance coeflcient is constant for all drainage areas.

INAGE SYSTEM EVALUATION - PHASE I1 Rational Method Calculation Sheet Source: Drainage Design Manual for Maricopa County, Arizona

Concentration Point I OOA Quarter Section Map Numbers 99D, IOOA, 100C

Outfall ID HW92D-W Drainage Area 0.01 sq miles


Runoff Coefficient

7.9 acres NA acres (reduced)* Weighted Runoff Coefficient* = QdU ,



Kb = Watershed Resistance Coefficient** ............................... 0.050

S = Watercourse Slope in feet/mile.. .................................... 79.2 ft/mile

Iterative Process to Determine 7, and Rainfall lntensity (1)

- I

- - -

T c - -


Q = CIA


.................... I = Rainfall Intensity in incheslhour ( I 0-yr storm) 3.95 inlhr

= Rainfall Intensity in inches/hour (1 00-yr storm). .................. 5.89 idhr A = Drainage Area* (contributing areas only) in acres ................ 7.9 acres

........................................... = 10-yr Peak Discharge in cfs 26 cfs ........................................ Q~oo = 100-yr Peak Discharge in cfs 39 cfs

* The drainage area is reduced by 25% of the medium density and medium to low density residential areas to account for retenfion occuring wifhln walled back yards. This reduced drainage area Is used when calculating the weighted runoff coefficient,

as well as the peak discharge. *"For the purposes of this study, fhe watershed resistance coefficient is consfant for all drainage areas.

INAGE SYSTEM EVALUATIO Rational Method Calculation Sheet Source: Drainage Design Manual for Maricopa County, Arizona

Concentration Point 108B Quarter Section Map Numbers



107B, 108A, B, C, D, & 116A, 6, D

MH-624 0.05 sq miles 1.41 sq miles 1.46 sq miles


Description of Land Use Runoff Coefficient (C) I

Total 31.5 acres

NA acres (reducedy. Weighted Runoff Coefficient* =

S t e ~ 2: Determine Time of Concentration fl,)

L = Length of the Longest Flow Path in feet ........................... 10,560 feet .............................. K b = Watershed Resistance Coefficient**. 0.050

S = Watercourse Slope in feetlmile.. .................................... 79.2 ft/mile


- - I ' - -

T C - -


Q = CIA

......................................... C = Runoff Coefficient (weighted). 0.83 .................... I = Rainfall Intensity in incheslhour (10-yr storm) 2.40 inlhr ................... = Rainfall Intensity in incheslhour ( I 00-yr storm) 3.53 inlhr

A = Drainage Area* (contributing areas only) in acres ................ 31.5 acres .................. ..................... Qlo = 10-yr Peak Discharge in cfs .., 63 cfs .......................................... Q~oo = 100-yr Peak Discharge in cfs 92 cfs

* The drainage area is reduced by 25% of the medium density and medium to low density residential areas to account for retention occuting

wifhin waNed back yards. This reduced drainage area is used when calculating the weighted runoff coefficient,

as well as the peak discharge. HFor the purposes of this study, the watershed resistance coefficient is constant for all drainage areas.

final summary report drainage system evalutation phase ii · 2020. 9. 17. · drainage system...

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