PIMA COUNTY REGIONAL FLOOD CONTROL DISTRICT

WITH OPTIONAL LOCAL SCOUR AT ABUTMENTS AND BRIDGE PIERS, WITHOUT LOCAL SCOUR AT DROPS OR LONG TERM DEGRADATION

Please read and understand the following important application notes regarding this program:

MAXIMUM ANTICIPATED SCOUR DEPTH ( ZT ) FOR SIMPLE CURVED AND STRAIGHT REACHES OF NON-REGIONAL SAND BED CONVEYANCES

1. This spreadsheet is best viewed using 1152 by 864 (or finer) screen resolution, and with EXCEL's horizontal and vertical scroll bars turned off. This will fit the entire worksheet at the "MAXIMUM ANTICIPATED SCOUR DEPTH" (MASD) tab to the limits of your computer screen. You can change your screen resolution using the Windows operating system. Scroll bars are removed in EXCEL through the Tools menu, followed by the Options button, then the view tab. Uncheck both vertical and horizontal scroll bars; move through worksheet by clicking on a cell and using arrow keys.

2. This spreadsheet will accept hydraulic characteristics for up to 5 separate conveyances. Each of these conveyances may be individual complete hydraulic cross sections, or each may be only a subsection of an individual hydraulic cross section. If your application is one of calculating maximum anticipated scour depth for an encroachment within the Erosion Hazard Setback (EHSB) of the main channel portion of a hydraulic cross section, then hydraulic characteristics for the main channel portion of the hydraulic cross section would be input into the worksheet. Similarly, the hydraulic characteristics input to the worksheet would be for the main channel if calculating local scour depth for piers and/or abutments located within the main channel, or within the EHSB of the main channel. However, if your application is maximum anticipated scour depth calculation for a development within the floodplain but beyond the EHSB of the main channel, then the hydraulic characteristics input into the worksheet would be for the appropriate overbank protion of the hydraulic cross section. Maximum anticipated scour depth calculations in sheet flow areas would use hydraulic characterists for a relatively flat hydraulic cross section which may or may not have a defined main channel.

3. Hydraulic characteristics for each of the 5 separate conveyances are typically derived from HEC-2 or HEC-RAS. These characteristics in the form of output from HEC-2 or HEC-RAS (or any other hydraulic program, for that matter) may be pasted into the appropriate cells of the worksheet at the "RAS OUT" tab. The worksheet at the "MAX ANTICIPATED SCOUR DEPTH" (MASD) tab automatically references data pasted accordingly in the RAS OUT worksheet. If you wish to manually input some of all of the hydraulic characteristics, this is accomplished by overwriting the unprotected refrencing equations in the blue-dot shaded cells of the MASD worksheet.

4. Because this spreadsheet does not perform normal depth or backwater calculations (you to execute HEC-2, HEC-RAS, FLOWMASTER, or other normal depth or backwater program to evaluate the hydraulic characteristics, and then input them into the worksheet), it is possible to manually input combinations of hydraulic characteristics which cannot be attained physically. It is your responsibility to verify that the hydraulic characteristics which you input into the spreadsheet actually represent the problem you are working with.

5. This spreadsheet has the ability to calculate local scour components due to piers or abutments. In addition, this spreadsheet can calculate these components by two methods: that prescribed in the publication titled: Standards Manual for Drainage Design and Floodplain Management in Tucson, Arizona (7/98), and that prescribed in the publication titled: Evaluating Scour at Bridges (5/01). The latter publication is also referred to as FHWA HEC-18. Links for both publications are presented below. Note that in calculating these local scour components, a separate flow depth may be entered for the pier scour calculations but not for the abutment calculations. Abutment calculations use the hydraulic depth for the conveyance. In addition, a separate Safety Factor (SF) may be entered for these local scour components.

http://tdotmaps.transview.org/mandr/Download/ http://www.fhwa.dot.gov/engineering/hydraulics/library_arc.cfm?pub_number=17&id=37

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• Blue shaded cells are for input data and information.

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• Screen Resolution of 1152 x 864 w/o scroll bars will display worksheet on one screen.• Yellow shaded cells are for final calculated output. • To avoid "DIVIDE BY ZERO" ERROR, erase data using: RT CLK, CLEAR CONTENTS.• Equations in blue-dot shaded cells may be overwritten. • To calculate scour at more sections, right click • Non-colored (white) shaded cells are calculated or copied. tab and create additional copies of the worksheet.

(form rev. 11/05/08)PIMA COUNTY REGIONAL FLOOD CONTROL DISTRICT

WITH OPTIONAL LOCAL SCOUR AT ABUTMENTS AND BRIDGE PIERS, WITHOUT LOCAL SCOUR AT DROPS OR LONG TERM DEGRADATION

Please read and understand the following important application notes regarding this program:

) FOR SIMPLE CURVED AND STRAIGHT REACHES OF NON-REGIONAL SAND BED CONVEYANCES

1. This spreadsheet is best viewed using 1152 by 864 (or finer) screen resolution, and with EXCEL's horizontal and vertical scroll bars turned off. This will fit the entire worksheet at the "MAXIMUM ANTICIPATED SCOUR DEPTH" (MASD) tab to the limits of your computer screen. You can change your screen resolution using the Windows operating system. Scroll bars are removed in EXCEL through the Tools menu, followed by the Options button, then the view tab. Uncheck both vertical and horizontal scroll bars; move through worksheet by clicking on a cell

2. This spreadsheet will accept hydraulic characteristics for up to 5 separate conveyances. Each of these conveyances may be individual complete hydraulic cross sections, or each may be only a subsection of an individual hydraulic cross section. If your application is one of calculating maximum anticipated scour depth for an encroachment within the Erosion Hazard Setback (EHSB) of the main channel portion of a hydraulic cross section, then hydraulic characteristics for the main channel portion of the hydraulic cross section would be input into the worksheet. Similarly, the hydraulic characteristics input to the worksheet would be for the main channel if calculating local scour depth for piers and/or abutments located within the main channel, or within the EHSB of the main channel. However, if your application is maximum anticipated scour depth calculation for a development within the floodplain but beyond the EHSB of the main channel, then the hydraulic characteristics input into the worksheet would be for the appropriate overbank protion of the hydraulic cross section. Maximum anticipated scour depth calculations in sheet flow areas would use hydraulic characterists for a relatively flat hydraulic cross section which may or may not have a defined main channel.

3. Hydraulic characteristics for each of the 5 separate conveyances are typically derived from HEC-2 or HEC-RAS. These characteristics in the form of output from HEC-2 or HEC-RAS (or any other hydraulic program, for that matter) may be pasted into the appropriate cells of the worksheet at the "RAS OUT" tab. The worksheet at the "MAX ANTICIPATED SCOUR DEPTH" (MASD) tab automatically references data pasted accordingly in the RAS OUT worksheet. If you wish to manually input some of all of the hydraulic characteristics, this is accomplished by overwriting the unprotected refrencing equations in the blue-dot shaded cells of the MASD worksheet.

4. Because this spreadsheet does not perform normal depth or backwater calculations (you to execute HEC-2, HEC-RAS, FLOWMASTER, or other normal depth or backwater program to evaluate the hydraulic characteristics, and then input them into the worksheet), it is possible to manually input combinations of hydraulic characteristics which cannot be attained physically. It is your responsibility to verify that the hydraulic characteristics which you input into the spreadsheet actually represent the problem you are working with.

5. This spreadsheet has the ability to calculate local scour components due to piers or abutments. In addition, this spreadsheet can calculate these components by two methods: that Standards Manual for Drainage Design and Floodplain Management in Tucson, Arizona (7/98), and that prescribed in the publication titled: Evaluating Scour

(5/01). The latter publication is also referred to as FHWA HEC-18. Links for both publications are presented below. Note that in calculating these local scour components, a separate flow depth may be entered for the pier scour calculations but not for the abutment calculations. Abutment calculations use the hydraulic depth for the conveyance. In addition, a

http://www.fhwa.dot.gov/engineering/hydraulics/library_arc.cfm?pub_number=17&id=37

• Screen Resolution of 1152 x 864 w/o scroll bars will display worksheet on one screen.• To avoid "DIVIDE BY ZERO" ERROR, erase data using: RT CLK, CLEAR CONTENTS.• To calculate scour at more sections, right click MAX ANTICIPATED SCOUR DEPTH tab and create additional copies of the worksheet.

INPUT OUTPUTDATE FILE FILE SUMMARY OF CHANGES:

6/2/2009 SCOUR08 SCOUR09

3/29/2011 SCOUR09 SCOUR10 1. Added an automatic date field to the MASD worksheet;2. Corrected the formula behind cell AR45 of the MASD worksheet

1. Added CHRONOLOGY worksheet in order to track changes to the Maximum Anticipated Scour Spreadsheet.

2. Modified SMDDFM Abutment scour calculations to remove HIRE factor (K2 = (U/90)0.13) to adjust for angle of embankment with respect to bank. In relation to this change, also modified this method to calculate abutment scour exactly as illustrated in the SMDDFM, and using the same variable identifications as those used in the SMDDFM. Finally, modified Abutment Tab to clarify the meaning of Ua.

3. Modified HEC-18 abutment scour calculations to reflect L' representing the length of obstructing embankment, measured normal to direction of flow (to be consistent with the definition of this variable in the HEC-18 book). Also modified associated Abutment Tab to clarify this meaning.

1. Added an automatic date field to the MASD worksheet;2. Corrected the formula behind cell AR45 of the MASD worksheet

1. Added CHRONOLOGY worksheet in order to track changes to the Maximum Anticipated Scour Spreadsheet.

2. Modified SMDDFM Abutment scour calculations to remove HIRE factor (K2 = (U/90)0.13) to adjust for angle of embankment with respect to bank. In relation to this change, also modified this method to calculate abutment scour exactly as illustrated in the SMDDFM, and using the same variable identifications as those used in the SMDDFM. Finally, modified Abutment Tab to clarify the meaning of Ua.

3. Modified HEC-18 abutment scour calculations to reflect L' representing the length of obstructing embankment, measured normal to direction of flow (to be consistent with the definition of this variable in the HEC-18 book). Also modified associated Abutment Tab to clarify this meaning.

PIMA COUNTY REGIONAL FLOOD CONTROL DISTRICT Date: 5/9/2023(form rev. 06/01/09)

WITH LOCAL SCOUR AT ABUTMENTS AND BRIDGE PIERSW/O LOCAL SCOUR AT DROPS OR LONG TERM DEGRADATION ADDRESS Project Address

NAME Data Sheet PreparerStep 1. Enter Project Information. N/A N/A N/A N/A N/A Conveyance Subsection Step 2. Bend Scour? Enter N if no bend scour. SEC = 0 0 0 0 0 Description

If Yes, Enter α. α = N N N N N (deg) Step 3a. Abutment scour per SMDDFM? Enter N if no. N N N N N (ft) Length of abutment projected normal to flow

N N N N N (deg) Slope angle of abutment face from horizontal

Step 3b. Abutment scour per HEC-18 (FHWA NHI 01-001 5/01)? L' = N N N N N (ft) Length of abutment projected normal to flowEnter N if no local abutment scour. N N N N N (dim)

N N N N N (deg)

Step 4a. Pier scour per SMDDFM? N N N N N (ft) Pier width, including anticipated debris blockageEnter N if no local pier scour. L = N N N N N (ft) Length of pier wall

N N N N N (ft) Flow depth upstream of pier (blank = max depth)RF = N N N N N (dim)

N N N N N (deg) Angle of approach flow in relationship to pier wall

Step 4b. Pier scour per HEC-18 (FHWA NHI 01-001 5/01)? N N N N N (ft) Pier width, including anticipated debris blockageEnter N if no local pier scour. L = N N N N N (ft) Length of pier wall

N N N N N (dim)N N N N N (dim)N N N N N (deg) Flow direction with respect to pier wallN N N N N (ft) Flow depth upstream of pier (blank = max depth)N N N N N (mm) Grain size for which 50% of bed material is finerN N N N N (mm) Grain size for which 95% of bed material is finer

Step 5. Enter safety factor for local (pier, abutment) scour. SF = 1.3 1.3 1.3 1.3 1.3 (dim) Blank = 1.3; text = 0

Step 6. Enter hydraulic characteristics for up to 5 sections in the blue fields below. HEC-RAS output may be pasted into RAS OUT tab to facilitate data entry.

INPUT HYDRAULIC CHARACTERISTICS OF CONVEYANCE CALCULATED CHARACTERISTICS S V A T WSL ELMN QE (fps) (ft) (ft) (ft) (dim) (cfs) (ft) (ft) (dim) (dim) SMDDFM SMDDFM SMDDFM SMDDFM SMDDFM HEC-18 HEC-18 (ft)C wsl-elmn Eq 8.3 Eq 6.4 Eq 6.6 Eq 6.5 Eq 6.9 6.11/6.12 Eq 6.1 Eq 7.1/7.2 Eq 6.3

0 0.0 0.0 0.0 0.0 0.0 0.000 0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.00 0.0 0.0 0.00 0.0 0.0 0.0 0.0 0.0 0.000 0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.00 0.0 0.0 0.00 0.0 0.0 0.0 0.0 0.0 0.000 0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.00 0.0 0.0 0.00 0.0 0.0 0.0 0.0 0.0 0.000 0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.00 0.0 0.0 0.00 0.0 0.0 0.0 0.0 0.0 0.000 0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.00 0.0 0.0 0.0

MAXIMUM ANTICIPATED SCOUR DEPTH ( ZT ) FOR SIMPLE CURVED AND STRAIGHT REACHES OF NON-REGIONAL SAND BED CONVEYANCES

Bend angle (See BENDS tab)

ae =If Yes, Enter ae & θa. θa =

K1 = Coefficient for abutment shape (See ABUTMENTS tab)If Yes, Enter L', K1, & θ. θ = Abutment angle wrt bank (See ABUTMENTS tab)

bp =

If Yes, enter Y1, bp, L, Φp & RF. Y1 =Reduction factor for nose shape (See PIERS tab)

Φp = a =

If Yes, enter a, L, K1, K3, Φp, Y1, D50, & D95. K1 = Correction factor for nose shape (See PIERS tab)K3 = Correction factor for bed condition (See PIERS tab)Φp =Y1 =

D50 =D95 =

CALCULATED INDIVIDUAL SCOUR COMPENENTS (ft) SE YH YMAX Fu rC/T ZGS ZBS ZA ZLSP ZLSE ZLSP ZLSE ZLF ZT

(ft2)V*A A/T

PIMA COUNTY REGIONAL FLOOD CONTROL DISTRICT

WITH LOCAL SCOUR AT ABUTMENTS AND AT BRIDGE PIERSWITHOUT LOCAL SCOUR AT DROPS AND LONG TERM DEGRADATION

Area to Paste Output from HEC-RAS or Other Backwater / Hydraulic Analysis Program for Input into Scour SpreadsheetReach River Sta Profile Velocity Area

(ft/s)

MAXIMUM ANTICIPATED SCOUR DEPTH (ZT) FOR CURVED AND STRAIGHT REACHES OF NON-REGIONAL SAND BED CONVEYANCES

(ft2)

PIMA COUNTY REGIONAL FLOOD CONTROL DISTRICT

Tuesday, May 9, 2023(form rev. 11/05/08)

Area to Paste Output from HEC-RAS or Other Backwater / Hydraulic Analysis Program for Input into Scour SpreadsheetTop Width W.S. Elev Min Elev E.G. Slope

(ft) (ft) (ft) (ft/ft)

NON-REGIONAL SAND BED CONVEYANCES

PIMA COUNTY REGIONAL FLOOD CONTROL DISTRICT

WITH LOCAL SCOUR AT ABUTMENTS AND AT BRIDGE PIERSWITHOUT LOCAL SCOUR AT DROPS AND LONG TERM DEGRADATIONVariable Units Definition

α (deg) Projection angle of channel centerline from point of curvature to point which meets tangent to outer channel bankθ (deg)

(rad) Slope angle of abutment face, measured from the horizontal, for calculation of local abutment scour by the method of the SMDDFMΦp (deg) Flow diredtion with respect to pier wallπ (dim) Ratio of circumfrence to diameter of a circle; 3.14159A (sq.ft) Cross sectional flow area of conveyance

(ft) Embankment or encroachment length, measured normal to flow direction for calculation of local abutment scour by the method of the SMDDFM(ft) Pier width measured normal to flow direction

ELMIN (ft) Thalweg elevation(dim) Upstream froude number

g(dim)

L (ft) Length of pier wallL' (ft) Embankment or encroachment length, measured normal to flow direction for calculation of local abutment scour by the method of HEC-18Q (cfs) Discharge within conveyance

RF (dim) Reduction factor based on pier shape (see TABLES tab)(ft) Radius of curvature along centerline of channel at cross section

(dim) Ratio of radius of curvature of centerline of bend in a conveyance, to top width of flow in the conveyanceSEC Identification number or letter for cross section

(dim) Energy slopeT (ft) Top width of flow for conveyanceV (ft/s) Average flow velocity in conveyance

WSEL (ft) Water surface elevation within conveyance(ft) Hydraulic depth(ft) Maximum flow depth

Z (dim) Horizontal run length for one foot of rise, for an embankment face(ft) General scour depth (general scour is caused by a discontinuity in the sediment-transport capacity of the flow), NON-REGIONAL WATERCOURSE ONLY(ft) Anti-Dune trough depth (Anti-dune scour is caused by the formation of anti-dunes in the bed of the conveyance)(ft) Local scour depth due to abutment or fill pad encroachment into flow path (Local scour occurrs due to abrupt changes in flow direction)(ft) Local scour depth due to pier within flow path(ft) Bend scour depth (bend scour is caused by transverse currents within the flow through a bend in the conveyance)(ft) Low flow thalweg depth(ft) Maximum anticipated scour depth (summation of all individual scour components, multiplied by a 30% safety factor to account for non-uniform flow distribution)

MAXIMUM ANTICIPATED SCOUR DEPTH (ZT) FOR CURVED AND STRAIGHT REACHES OF NON-REGIONAL SAND BED CONVEYANCES

Embankment angle to flow, Fig 7.1 Highways in the River Environment (HIRE), 12/01 (see TABLES tab). Θ<90θa

ae

bp

Fu

(ft/s2) Acceleration due to gravity, 32.2 ft/s2

K2 Factor to account for effect of embankment angle to flow on local scour due to embankment; K2 = (θ/90)0.13 (ref. Equ 7.16, HIRE 12/01).

rc

rc/T

SE

YH

YMAX

ZGS

ZA

ZLSE

ZLSP

ZBS

ZLF

ZT

PIMA COUNTY REGIONAL FLOOD CONTROL DISTRICT

Tuesday, May 9, 2023(form rev. 6/01/09)

Definition Projection angle of channel centerline from point of curvature to point which meets tangent to outer channel bank

Slope angle of abutment face, measured from the horizontal, for calculation of local abutment scour by the method of the SMDDFM

Embankment or encroachment length, measured normal to flow direction for calculation of local abutment scour by the method of the SMDDFM

Embankment or encroachment length, measured normal to flow direction for calculation of local abutment scour by the method of HEC-18

Ratio of radius of curvature of centerline of bend in a conveyance, to top width of flow in the conveyance

General scour depth (general scour is caused by a discontinuity in the sediment-transport capacity of the flow), NON-REGIONAL WATERCOURSE ONLYAnti-Dune trough depth (Anti-dune scour is caused by the formation of anti-dunes in the bed of the conveyance)Local scour depth due to abutment or fill pad encroachment into flow path (Local scour occurrs due to abrupt changes in flow direction)

Bend scour depth (bend scour is caused by transverse currents within the flow through a bend in the conveyance)

Maximum anticipated scour depth (summation of all individual scour components, multiplied by a 30% safety factor to account for non-uniform flow distribution)

SAND BED CONVEYANCES

Embankment angle to flow, Fig 7.1 Highways in the River Environment (HIRE), 12/01 (see TABLES tab). Θ<90° if embankment points downstream

Factor to account for effect of embankment angle to flow on local scour due to embankment; K2 = (θ/90)0.13 (ref. Equ 7.16, HIRE 12/01).

TABLE 6.1: REDUCTION FACTORS (RF) TO BE USED WHEN APPLYING SCOURFORMULAS FOR SQUARE-NOSED PIERS TO OTHER SHAPES(assuming equally projected widths of piers)

Type of Pier Reduction FactorSquare Nose 1.0Cylinder 0.9Round Nose 0.9Sharp Nose 0.8Group of Cylinders 0.9

Tuesday, May 9, 2023REDUCTION FACTORS (RF) TO BE USED WHEN APPLYING SCOUR