Sewer Gems

 

Sanitary Sewer Design and Modeling Workshop Featuring Bentley Systems SewerGEMS Slavco Velickov, PhD Bentley Systems

 

Scope • Steady hydraulics • Model building • Unsteady hydraulics

• Pumps and force mains • Pressure sewers

• Dry weather loading • Sanitary sewers

  • Monitoring/rehab • Geospatial data

• Combined Sewers • Designing new systems

• Load building • Water quality

 

Sanitary Sewer System Overview • Con onve vey y was wasttew ewat ater er to to tre treat atme ment nt • In some some cas cases es st stor ormw mwat ater er is is als also o conv convey eyed ed • Primary co components ar are:  – gravity pipes  – connecting manholes or access chambers  – pump stations and pressure mains • Most Most sy syst stem ems s des desig igne ned d for for gra gravi vity ty fl flow ow

 

Types of Conveyance • Gravity flow • Surcharged gr gravi vitty flow • Inverted siphons • Pre ress ssur ure e fl flow ow in fo forc rce e mai ains ns • Pressure sewers • Vacuum se sewers

 

Applications of Collection System Models • Design • Lo Long ng-r -ran ange ge ma mast ster er pl plan anni ning ng   • Operational pr problems • Regulatory compliance • “What if?” scenarios

 

Temporal Considerations • Steady State  – Used for design work  – Typically concerned with extreme conditions  –   • Uns nsttea eady dy (e (ext xten ende ded d pe peri riod od))  – Used when pumps cycling or storage in system are significant  – Routing hydrographs through system

 

The Modeling Process Select Modeling Software

Develop Alternatives

Learn Software

Document Results

Define Scope Of Project

Prepare System Description

Enter System Data

an Loading Data

Enter Loading Data

Collect Calibration Data

Verify Data

Initial Model

Calibrated Model

Apply Model

Develop Solution

e ne ore  Alternatives Model

 

Types of Flow • Open Channel Flow  – Flow with free surface exposed to to atmosphere • Pressure or Pipe Flow  – Flow in closed conduit under pressure

 

Wastewater • Incompressible • Turbulent • Newtonian Fluid • eys  ewton s aw o scos ty • In ty typi pica call was waste tewa wate ter, r, so solilids ds do don’ n’tt significantly affect viscosity significantly • Wa Wast ste e act activ ivat ated ed sl slud udge ge sti stillll New Newto toni nian an • Th Thic icke ken ned sl slud udge ge not not New Newto toni nian an

 

• Volume/time

FLOW

• m3 /s – cubic metres/second metres/second (SI) (SI) • L/s – litres/second 3

• • • • • •

 – – cubic feet/second feet/second (FPS) (FPS) gpm – gallons/minute MGD – million gallons/day ac-ft/day – acre-feet/day cufr cu fr/f /frrtn tntt - cu cubi bic c fur furlo long ngs/ s/fo fort rtni nigh ghtt ft3 /s

 

PRESSURE • Force/Area • Newton/square me metre - Pasc sca al (S (SI) • kPa – kiloPascal • • • •

 – psf – pound/square fo foot (F (FPS) psi – pound/sq squ uare in inch ch (U (US S typ ypiica call) atm – atmosphere (14.7 psi) pound?

• Gage vs. absolute

 

Flow Classification Scheme Uniform Steady

Unsteady

Normal depth Lon  channel

Nonuninform Manholes Backwater

Pump cycling Wet weather

 

Conservation Equations • Conserva vattion Pr Principles  – Mass  – Energy • Conservation of Mass re uires that  – Inflow - Outflow = Rate Rate of change in storage  – If Inflow = Outflow, no storage occurs  – If Inflow > Outflow, excess is stored  – If Inflow < Outflow, water level drops

 

Velocity and Flow • Veloc Velociti ities es var vary y ac acros ross s flo flow w giv giving ing a vel veloc ocity ity pro profile file.. • In pra pract ctic ical al app applilica cati tion ons, s, aver averag age e velo veloci city ty can can be used:

Q

V = average fluid velocity

=  A

 = p pe ne ow ra e A = cross-sectional area of flow

• Subst Substitu itutin ting g the the cro crossss-se secti ction onal al area area of a full full cir circu cular lar pipe the equation becomes:

V   =

4Q

 D

2

D = diameter

 

Conservation of Energy • Wate Waterr flo flows ws fr from om a reg regio ion n of of hig highe herr ene energ rgy y to to a region of lower energy • En Ener ergy gy te term rms s are are ty typi pical cally ly ex expr press essed ed as he head ad • Co Cons nsid ider er th the e en ener ergy gy te term rms s for for pr pres essur suriz ized ed pipe flow

 

Conservation of Energy For steady, incompressible full pipe flow steady 2 1

γ  

+  z 1 +  

1

2g

2

=

2

γ  

+  z 2 +  

2

2g

+   h  f 

p = fluid pressure γ  = specific weight of fluid Z = elevation above an arbitrary datum plane V = fluid velocity, averaged over a cross-section g hf = = acceleration headloss dueoftogravity friction

 

Conservation of Energy • For Fo r ope open n cha chann el fl flow ow, , pre press ssur ure e hea head d is is expressed in nnel terms of depth of flow (y) • Th The e ene energ rgy y equ equat atio ion n for for op open en ch chan anne nell

 y 1 +  z 1 +    

v 12 2g

=  y 2 +  z 2 +  

v 22 2g

+ h  f 

 

Energy Grade Lines Total energy at-a-point in the fluid system

P P

 

= 

2

v   2g 2

Open channel  flow:  EGL   = y + z +  v 2g

 

Hydraulic Grade Lines Sum of the pressure and elevation head terms at-a-point

Pipe  flow :   HGL =

γ  

+  z

Open channel:  HGL   = y + z

 

Friction Head Loss Equations • En Ener ergy gy is is used used to to over overco come me fri frict ctio ion n and/ and/tu turb rbul ulen ence ce • Seve Se vera rall equa equati tion ons s are are avai availa labl ble e to ca calcu lcula late te hea head d loss:  – Manning  –  – Kutter/Chezy  – Hazen-Williams • Mo Most st he head ad lo loss sses es is wa wallll fr fric icti tion on • Mi Mino norr los losse ses s oft often en sm smal alll in in com compa pari riso son n

 

Manning’s Equation Most commonly used in US

k  2 / 3 1 / 2 Q =  A Rh S  k = 1.49 for U.S. customary units and 1.0 for SI units A = cross sectional area of flow Rh = Hydraulic radius S = slope of the energy line = So for uniform flow n = Manning’s roughness coefficient

 

Manning’s Equation Manning’s n-value is viewed as a roughness coefficient, but it is actually influenced by many factors: • Wall roughness • Depth of flow • Viscosity • Obstructions • Diameter • Velocity

• Stage and Discharge • Silting and Scouring

 

Darcy-Weisbach Equation Widely Wid ely used used – the theore oretic ticall ally y correct correct

 L

h

=

2

v  D 2g

hf = headloss f = Darcy-Weisbach friction factor L = pipe length V = average pipe velocity g = gravitational constant

 

Moody Diagram

f 

Reynolds Numbe

 

Kutter/Chezy Equation Sometimes used in various parts of the world

V  = C   Rh S  V = Mean velocity (ft/s, m/s) C = Roughness coefficient R = Hydraulic radius (ft, m) S = Friction slope (ft/ft, m/m)

 

Hazen-Williams Equation Frequently used in North America for pressure C  f  L 1.852 h L   = 1.852 4.87 Q hL = pipe friction head loss L = pipe length C = Hazen-Williams C factor D = diameter Q = flow rate Cf = unit conversion factor

 

Minor Losses Any feature that causes the flow to accelerate, decelerate, change direction, or change crosssectional area results in loss of energy. Minor losses typically occur in sewer systems at man o es

h = K   M 

 M 

v

2

2g

hm = the minor head loss Km = a minor loss coefficient

 

Minor Losses • Mi Mino norr losse losses s occ occur ur at at man manho hole les, s, whe where re the there re ar are e entrance and exit losses and changes in flow direction • Values of Km for manholes range from 0.5 to 1.0 • Meth Method ods s for for ca calc lcul ulat atin ing g jun junct ctio ion n loss losses es in SewerCAD  –  –  –  –

Absolute Standard Generic HEC-22 Energy Energy

 – AASHT AASHTO O

 

Specific Energy • Spec Sp ecif ific ic En Ener ergy gyin(E (E) ) - to tota tal l en ener ergy gy at-a at -a-p -poi oint nt (cross-section) open channel flow with respect to channel bed: 2

 E  =  y +   v 2g

• Fo Forr a gi give ven n di disc scha harg rge e Q = V*A Q  E  =  y +   2g  A 2

2

 

Specific Energy Plot of the depth of flow vs. specific energy for a 12 inch pipe (yc is the critical depth) 1. 1.0 0

y c   = .

.

Q = 3.0

0. 0.6 6 y - ft

y c = 0.42 0. 0.4 4

y c = 0.29

Q = 1.0

0. 0.2 2

Q = 0.5 0. 0.0 0 0 .0

0 .2

0 .4

0 .6

0.8

Specific Energy - ft

1 .0

1 .2

1 .4

 

Froude Number • Dimens Dimension ionles less s para paramet meter er to cla classi ssify fy op open en ch chann annel el flo flow w • Th The eF Fro roud ude e Num Numbe berr is eq equa uall to 1 at at cri critic tical al de dept pth h F

=

V  gDh

flo ow: • Classification of fl  – Depth of flow is higher higher than yc , F < 1, flow is subcritical  – Depth of flow is equal equal to yc , F = 1, flow is critical  – Depth of flow is lower lower than yc, F > 1, flow is supercritical

 

Non-Uniform Flow Most channels are non-prismatic  – Sanitary sewers are non-prismatic due to • Pr Pres esen ence ce of ma manh nhol oles es • Chan es in i e diameter, slo e and direction • Fl Flow ow ma may y be no nonn-un unif ifor orm m in in a pr pris isma mati tic c channel due to the influence of a control  – Backwater created by a high tailwater tailwater depth  – Drawdown at a free outfall

 

Control • A cha chann nnel el fe feat atur ure e (st (stru ruct ctur ural al)) wit with h a un uniq ique ue (1:1) relationship between depth and discharge  – Free overfall at the end of a mild channel  – Weirs and Flumes (critical controls)  – ong pr sma c c anne con ro reac • Re Regu gula late tes s (con (contr trol ols) s) th the e sta state te of fl flow ow  – Subcritical flow is controlled by downstream conditions  – Supercritical flow is controlled by upstream conditions

 

Nonuniform flow controls Weir

Change in slope

 

Channel Classification • Chan Ch anne nell be bed d as slope slo pes s ,ar are e cl clas assi sifi fied ed , mild  steep  hydraulically , critical  horizontal or adverse  • F or iven flow r te th the bed slo e is called:  – Mild if yn > yc  – Steep if yc> yn  – Critical if yn = yc

 

Assembling the Model

 

Data Requirements • • • • •

Network layout (system data) Hydraulic properties Sanitary flows (dry weather) Inflow and infiltration (wet weather) Operation data

• Calibration data

 

Ne Netw twor ork k Dat Dataa- Sy Syst stem em La Layo yout ut Data • coord rdiinates of of ea each pi pipe • • • •

segment and manhole locati tio ons of wet wells, pumps pu mps,, app appur ur en enan ances ces pip ipe e co con nnec ecti tivi vity ty,, le len ngth ths s pipe di diameters, ma materi ria als pipe invert levels and manhole elevations

Data • mapSources s – paper/CAD • constr tru uction/a /as s-b -bu uilt drawings • corpora e  sys em • asset-management systems • work orders • field survey

 

Hydraulic Properties Data

• pipe roughness • pump curves

Data Sources

• manufacturers’ specifications •• c su su litoenrtartaucrteorva lubem s ittals • field tests

 

Sa Sani nita tary ry Fl Flow owss- Dr Dry y We Weat athe herr Data

Data Sources

• flows diurnal patterns • projections

• census data

• location of each source • min, max, mean daily

• metering • maps, ae aerial ph photos

 

Inflow low and Inf Infilt iltrat ration ion-- Wet We Weath ather er Inf Data

• infiltration ra rate fo for each pipe segment or sub-basin • locations of inflows • quantities of inflow

Data Sources

• field inspection • measurements • analysis of tre rea atm tme ent plant flows • hydrologic analysis • literature values

 

Operation Data Data

• settings for pump operation • sett ttiings of of fl flow-contro roll structures • control st strategies • outlet controls

Data Sources

• interviews with operations personnel • operations records and manuals • field inspection

 

Calibration Data Data

• recorded de depth, ra rate of flow • fr fre equency/locati tio ons of of overflows • Precipitation da data

Data Sources

• field inspection an and measurements • operations re records • weather records • flow-monitoring program

 

Types of Simulations Steady Sizing, Good system

Wet

Sizing, I/I system

EPS Design

Overflows, troubleshooting

 

Defining Gravity Pipes • Internal diameter • Length (s (sch che ema mati tic c or or sc scale led d) • Material  

'

• Shape • In Inve vert rt ele eleva vatio tions ns (set (set to to ups upstre tream am/d /dow owns nstre tream am pipe) • Number of sections

 

Siphons (Depressed sewers) • • • •

Desig Des igne ned d dip dip in a gra grav vit ity y se sewer Occu Oc curs rs wh when en se sewe werr mus mustt pas pass s und under er st stru ruct ctur ures es Sewe Se werr line line is is bel below ow the the HG HGL, L, fu fullll,, and and und under er pre press ssur ure e Design Des igned ed wit with h smal smaller ler pip pipes es to mai mainta ntain in sel self-c f-clea leanin ning g ve oc oc es

 

Defining Manholes • Invert elevati tio on- bott tto om of pipe entering manhole • Rim elevation • Structure size- common diameter in US is 4 ft • Drop manhole- incoming sewage transported down vertical shaft

 

Junction Chamber • Mo Mode dell spe speci cial al und under ergr grou ound nd str struc uctu ture res s • No loading • In Inpu putt par param amet eter ers s nece necess ssar ary y to ph phys ysic ical ally ly defin define ea  junction chamber chamber are:  –   – Ground Elevation Elevation  – Structure Diameter Diameter  – Top Elevation Elevation  – Bottom Elevation Elevation

 

Defining Outlets • Rep Repre res sents tr tre eatm tme ent pla plan nt, pump station, CSO, SSO or end of study area • Specify ta taiilwate terr depth  –    – Full pipe  – Critical depth • Crit Critic ical al de dept pth h ap appr prop opri riat ate e wh when en pipe freely discharges

 

MODELING PRACTICE • Dat ata a Ent Entry ry • Frequent che checking • Tria riall runs runs and GUI GUI can can show show major major data data entr entry y error errors s • Using Model • Pl Plan an ru runs ns be befo fore re yo you u mak make e th them em • ry  erent scenar os an a ternat ves • Ke Keep ep tr trac ack k of of runs runs an and d bac backu kup p file files s • On Ongo goin ing g Pract Practic ices es • La Large rge ini initia tiall inves investme tment nt in mod modeli eling ng and and traini training ng • Keep go good re records • “H “Hit it by a tru truck ck”” pri princ ncip iple le - so tr trai ain n oth other ers s

 

TRADITIONAL METHOD OF MANAGING RUNS Input File

MODEL

Output File

Input File 1

Output File 1

Input File 2

Output File 2

Input File 3

Output File 3

Input File 4

Output File 4

Input File 5

Output File 5

Input File 6

Output File 6

Input File 7

Output File 7

Input File 8

Output File 8

Input File 9

.

.

.

Output File 9

 

SCENARIO MANAGER TERMINOLOGY • Scen Scenar ario io = sin singl gle e run run of mo mod del  – contains type of run  – teointers alte • Al Alt rna rn ative ves sto= alternative datrnative a se sett data  – buildi building ng block block of scenarios scenarios • Inher Inherita itance nce = bu builildi ding ng al alter terna nativ tives es an and d scenarios from previous

 

SCENARIO MANAGER Scenario Cycle Build Model (Base Scenario)

Calculate Scenario

Create New

Review Results

Alternatives -Topology -Physical -Boundary Conditions -Initial Conditions - y ro ogy -Output -Rai -R ainf nfal alll – ru runo nofff -Water quality -User data extensions extension s

Scenario Add/Modify Alternatives

 

TOPOLOGICAL ALTERNATIVES Make indi individu vidual al elements elements active active or or inactive inactive Great for “future” scenarios

 

Getting at Results • Property grid • Flex tables • Color coding • Annotation • Profiling

 

Managers • Scenario • Alternatives • Calc Options

• Selection sets • Queries • Drawing navigator

• Profiles • Symbology • Animation

• Prototypes • Flex Tables

 

Unsteady Flow Hydraulics

 

What does SewerGEMS do? Given: System Physical map properties Loading data (Water Quality)

Determines: Flow, velocity, depth in each conduit Level in each manhole, pond, tank  (water Quality)

 

Evolution of Models Sanitary

Stormwater

Steady State

SewerCAD

StormCAD

Simple Routing

SewerCAD SewerCAD  

Pond Pack  orm

SewerGEMS

Civil Storm

Fully Dynamic (St. Venant)

 

Elements • Point

 – Manhole  – Pressure unction  – Cross section  – Junction chamber  – Catch basin  – Pump  – Wet well  – Pond outlet

• Line  – Conduit  – Channel  – Pressure pipe  – Gutter

• Polygon  – Catchment  – Pond

 – Outfall  

Basic Principles Conservation Conservation of Mass S (t + ∆t ) = S (t )  +  I (t ) ∆t − Q (t ) ∆t 

Conservation of Energy     y1 + z1 +

2 1

v

2g

=  y2 + z 2 + 

v

2 2

2g

Manning’s

k  2 / 3 1 / 2 Q = n  A Rh S 

+ h f 

 

What Causes Unsteady Flow? • Pumps cycling • Wet weather I/I • Batch processes   • Oc Occu curs rs in in sani sanita tary ry,, comb combin ined ed and and sto storm rmwa wate terr syst system ems s

 

Unsteady Flow • Can’ Can’tt just just sli slide de hyd hydro rogr grap aph h down downst stre ream am • In Incr cre ease in fl flo ow shows up as  – Increase outflow  – • Depen end ds on natu ture re of sys yste tem m

 

Hydrograph Routing Short distance Steep slope Flow Long distance Mild slope

Time

 

Routing Methods • Hydrologic  – Mukingum  – Puls  – Kinematic wave wave  – Convex • Hydraulic  – St. Venant Venant equations

 

Fully dynamic model? Solves full St. Venant equations for 1-D flow in open channels Continuity

∂t 

+  y

∂ x

+u

∂ x

=0

)

Momentum

∂u ∂t 

+u

∂u ∂ x

+g

∂ y ∂ x

− g ( S  x −  S  f  ) = 0

 

Normal Depth

B 1 cfs  A  1 cfs

 

varied surcharged flow Gradually varied flow

B 2 cfs  A  2 cfs

 

Overflow

HGL

1 cfs

B 3 cfs  A  2 cfs

 

Backup

HGL

4 cfs

B 3 cfs  A  1 cfs

 

Bentley Dynamic Models • Solv Solve e ful fulll St. St. Vena Venant nt equ equat atio ions ns • Use stabl stable e imp implic licit it fin finite ite di diffe fferen rence ce sol solut ution ion • • • • •

B n FLDWAV Routes hydrographs Hand Ha ndle les s surch surchar argi ging ng,, overf overflo lows ws,, backu backups ps Hand Ha ndle les s pipe pipes, s, cha chann nnel els, s, pon ponds ds,, pump pumps s Use sed d in CS CSD, D, SewerG rGE EMS

 

Special Situations

• Surcharging • Dry pipes • Drop st structures • Pump cy cycling

 

Handling Pressure Flow

 

Start Type • • • •

Can start with dry pipe Can Ca n “w “warm rm-u -up p” mod mode el up up to to tim time e0 Warm Wa rm up ti tim me dep epe ends on on sys syste tem m Experi rime men nt to to fi fin nd be best wa warm up

Q

t  

Convergence Tips • • • • •

Avoid ve very sh short pi pipes Make Ma ke co comp mput utat atio ion n tim time e st step ep sh shor orte terr Move Mo ve NN-R R wei weigh ghtin ting g coe coeffi ffici cien entt clo close serr to to on one e Dec ecre reas ase e co comp mpu uta tati tion on dis dista tan nce Test with no weir flow

 

Graphing

A Picture is Worth 103 Words

 

Single Element Over Time • Show Shows s one one at attr trib ibut ute e for for on one e element over time

 

Scenario Comparison over Time • Used Used to com compa pare re si sing ngle le att attri ribu bute te ove overr time between scenarios

 

Element Comparison over Time • Co Comp mpar are e att attri ribu bute te fo forr an el elem emen entt over over time for single scenario

 

•

Element Scenario over Time Can Ca n inc inclu lude de di diff ffer eren entt ele eleme ment nts s and and scenarios for a single attribute over time

 

Graphing Controls • Gr Grap aph h Ser Serie ies s Opti Option on (Se (Sewe werG rGEM EMS S choi choice ces) s)  – Attribute (fields) (fields)  – Element  – Scenario

• Ch Char artt Opti Option ons s (Gra (Graph phic ics s choi choice ces) s)  – Chart tab • Ax Axis is,, ti titl tle, e, le lege gend nd • Cli Click ck on indi individ vidual ual seri series es prope properti rties es  – Series tab • Fo Form rmat at,, mar marks ks

 

Graphing Tips • Che Checki cking ng/un /unche checki cking ng “vi “visib sible le”” tu turns rns th thin ings gs on/off • Def Defau ault lt fo forr leg legen end d is is out outsid side; e; use “cu “custo stom” m” to move inside • Se Sett disp displa lay y num numbe berr of of dig digit its s in in “da “data” ta” ta tab b or in options • Back Backgr grou ound nd un unde derr “pa “pan nel el”” tab tab • “M “Mar arks” ks” re refe fers rs to to plac placin ing g actu actual al val value ue on on graph

• Th Ther ere e is is no Un Undo do ; Sav Save e work work fre frequ quen entl tly y  

Terminology Title

Subtitle

Mark 

 Axis Title

 Axis Label

2000

Series Foot

Panel

 

Dynamic Wave Routing Because life is dynamic

 

Sanitary Systems

 

Sanitary Sewer Systems • De Desi sign gned ed fo forr san sanit itar ary y loa loads ds • Sh Shou ould ld be mi mini nima mall wet wet we weat athe herr I/ I/II  – Inflow / Infiltration Infiltration  – Problem Problems s usuall usuall  caused b I/I  – Must understan understand d dry weather weather flow

• I/ I/II ent enter ers s thr throu ough gh de defe fect cts s  – Manhol Manholes es  – Joints  – Illega Illegall connections connections

 

Sanitary Sewer Modeling • System de design • Sys ysttem ca cap pac acit ity y ana analy lysi sis s • Stead raduall  varied flow anal sis • Overflows • Comp Complilian ance ce wi with th Ca Capa paci city ty man manag agem emen entt operation and maintenance (CMOM)

 

Sanitary Sewer Design • Dendritic la layout • Controlled by  – Loading  –  – Right of way and conflicts conflicts • Min pip ipe e siz ize e usu sua alllly y 8 in in..

 

Sanitary Sewer Overflows (SSO) • SSO no not pe permitted • Understand ca cause  – Mainten Maintenance ance roots   rease  – Lack of capacity (growth)  – RDII (wet weathe weatherr only)

• Mode Modell can can he help lp id iden enti tify fy ca caus use, e, remedial action

• Co Comb mbin ine e mode modeliling ng and and mon monit itor orin ing g  

Solving Overflows • Comp Compar are e mod model el wit with h mon monit itor orin ing g • Fi Find nd flow flow an and d hyd hydra raul ulic ic pr prop oper erti ties es that match monitoring • Propose solutions  – I/I control control  – Increase capacity  – Storage

Mode Mo dell pr prop opos osed ed so solu luti tion ons s  

Dry Weather Loads • Referred to as:

•Usage •Demand •Loading • Lo Load adss are are as assi sign gned ed to nod nodes es • Mu Must st ad add d in we wett wea weath ther er loa loads ds • Wi Wide de var variet iety y of dat data a sour sources ces

 

PLACING LOADS AT NODES

MH-35

MH-36

Q(load) << Q(in)

 

Steps in Loading Model • • • •

Current ye year av average da day Peak Pe akin ing g an and d te temp mpor oral al va vari riat atio ions ns Wet weather flflows Projections

 

Top Down  System Production Large

Subareas

Users

Load

 

Load

 

Customer Meter Records/ Unit Loads

Load

 

Load

 

Load

I/I?

 

Bottom Up   

Projections Loading •Spatial and temporal population projections •Usually provided by city or regional planners • Get others to “sign off” on populatio population n projections projections • Where will high growth be? Where will large water users be?    Alternative loading projections  Average  Average Load

1960

1970

1980

1990

2000

2010

2020

2030

 

 Year Population  Year Population 2000 540 2010 635 2020 710

Planning District

Existing Pipes Drainage

Divide

Placing Projected Load 

 

Loading Methods in SewerGEMS

• Sanitary lo loading

 – Hydrograp Hydrograph h  – Unit load load x count count (with pattern pattern))  – Base flow flow x pattern pattern

• n ow  – Fixed inflow  – Hydrograp Hydrograph h  – Base flow flow x pattern pattern

•• C riu Piaptechinmfieltn rat tru on noff  

Pattern

Hydrograph   s    f   c    ,   o    l    F

  r   e    i    l    i    t    l   u    M

Day 1

Day 2 Time

Day 3 Day 1

Day 2

Day

Time

 

Unit Loading • Unit load  – Home  – Restaurant per per customer  – Office per employee employee • Defa fau ult va values av available • ser prov es coun popu a on • Pa Patte ttern rn se setu tup p ass assig igns ns pa patte ttern rn to lo load ad ty type pe

 

Patterns •• M ulti ul tip p lier li er x b bas ase e f low lo w Base Ba se on fl flow ow me mete teri ring ng fo forr dry dry da day y • Ass ssig ign n pat patte tern rns s to to no node des s  –

 

,

• Re Repe peat at ea each ch pe peri riod od (2 (24 4 hrs hrs))

Flow

Time

 

Dry Weather Loading Patterns

Define patterns by demand types: e.g.. res e.g reside identi ntial al - ind indust ustria riall - co comme mmerci rcial al

• For For larg large e wate waterr user users, s, use use act actua uall wate waterr use patterns   • Li Lite tera ratu ture re va valu lues es ca can n prov provid ide e fir first st guess gues s – ve very ry sy syst stem em spe speci cifi fic c • Pa Patt tter erns ns ca can n var vary y by by sea seaso son/ n/da day y of of week

 

Patterns: Stepwise or Continuous STEPWISE

CONTINUOUS

TIME

 

Typical Loading Patterns

 

Flow Balance For given time period Load Lo ad = V( V(in in)) – V( V(ou out) t) +/ +/--

Storage

Define area where all flows and levels are known

Flow = Usage/Time

Multiplier = Flow/(Av Flow/(Average erage Flow)

 

Combined Sewers • Carr rry y wa wast ste ewa wate terr and and sto storm rmwa wate terr • Ov Over erfl flow ows s pe perm rmit itte ted d in we wett wea weath ther er • No dry weather overfl flo ows •

 

Key Terminology

Types of  Flow

 

 

Separate Sanitary Sewers

 

Combined Sewers

 

Typical CSO From System From System o Overfl

To Treatment Weir

Control

To Treatment

To Overflow  

Nine Minimum Controls • Proper O&M • Maxi xim mize use of st sto ora rag ge • Mo Modi dify fy pr pret etre reat atme ment nt re requ quir irem emen ents ts • • El Elim imin inat ate e dr dry y wea weath ther er CS CSOs Os • Cont Contro roll sol solid ids s and and flo float atab able les s • Po Pollllu ution pre reve ven nti tio on • Pu Publ blic ic n no oti tifi fica cati tion on of imp impac acts ts

• Mo Moni nito torr imp impac acts ts an and d con contr trol ols s  

Modeling Diversions • Dy Dyna nami mic c wav waver er ca calc lcul ulat ates es fl flow ow sp splilitt • Cont Contro roll str struc uctu ture res s (p (pip ipe e pro prope pert rty) y)  – Weir  – Orifice  – Functions Q = a(H-weir)b  – ep  vs. ow curve • Stability issues – small titime ste tep ps • Hydrologic ro rou utine – rati tin ng ta tab ble

 

Combined System Loading • Uses both In Infl flo ow and and Sanit ita ary • Sanitary - dry weather flflow • In Infl flo ow/I /In nfi filt ltra rati tio on - wet weath the er fl flo ow

 

Modeling CSOs • Dete Determ rmin ine e mag magni nitu tude de of ev even entt tha thatt cau cause ses s overflow • De Dete term rmin ine e vol volum ume e of of ove overf rflo low w vs. vs. eve event nt • From Fr even freque uenc ncy, y, ca can n ide ident ntify ify ov over erflo flow w voom umev e entt freq • Long term simulation

 

CSO Solutions • Sewer se separation • Sto tora rag ge of wet weath the er fl flo ow • No new new comb combin ine ed sy syst ste ems in EME MEA A • Comb Combin ined ed se sewe wers rs co comm mmon on el else sewh wher ere e • Modeling important

 

Selection Sets • Can Can def defin ine e gro group ups s of of ele eleme ment nts s for for gra graph phic ics s or or tables • Us Usef eful ul for for fi find ndin ing g thin things gs in in larg large e mode models ls • Can use  uer erie ies s to cr cre eate se sets ts • Vie iew w wit ith h Dra rawi win ng Nav avig iga ato torr

 

Query Manager Selection sets can Be manually created

Query is used to Create selection sets

Set Manager

Selection sets are used By drawing navigator to Determine elements for display

Drawing Navigator

 

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