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LECTURE 1INTRODUCTION

CEEGR 6977: HydrologySam Shamsi, Ph.D., P.E.

Adjunct ProfessorDepartment of Civil / Environmental & Chemical Engineering

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OUTLINEGeneral

Student teacher introductionSignup sheetScheduleTextbook GradingLearning objectives

Lecture No. 1HydrologyHydrologic cycleWatershedsDigital Elevation Models (DEM)Models

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ABOUT YOUR PROFESSORABOUT YOUR PROFESSORPrincipal, ATS-Chester Engineers, Pittsburgh, PA

Eighteen (18) yearsWater and wastewater engineeringHydrologic & hydraulic modeling and GIS

ProfessorUniversity of Pittsburgh, GIS and HydrologyPenn State University, Continuing EducationYoungstown State University, GIS and Hydrology

Education:Ph.D. (Civil Engineering), University of Pittsburgh, 1988

80+ publicationsBooks:

GIS Tools for Water, Wastewater, and Stormwater Systems, An ASCE Press Best-seller, 2002.GIS Applications for Water, Wastewater, and Stormwater Systems, CRC Press, 2005.

Professional Engineer in PA, WV, OH

Contact: ushamsi@chester-engineers.com412-809-6618 Office724-777-6909 Cell

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YOUR TURNPlease introduce yourself

Your nameYour program: undergraduate or graduateYour majorYour organization (if employed)Your profession (if employed)

Civil engineer, hydrologist, project manager, etc.

Your area of interest:Water Supply, Wastewater, Stormwater Management, etc.

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SCHEDULE

SPRING BREAK3/12/07

Final Examination155/7/07

380-38312,15Frequency Analysis144/30/07

350-37911Hydrologic Statistics134/23/07

Lumped Flow Routing 2124/16/07242-2718

Lumped Flow Routing 1114/9/07

Unit Hydrograph104/2/07211-2417

Unit Hydrograph93/26/07

Mid Term Examination83/19/07

Surface Water 273/5/07 127-1535Surface Water 162/26/07

99-1264Subsurface Water52/19/07

80-983Evaporation and Evapotranspiration42/12/07

507-51415HEC-HMS Workshop32/5/07

56-80179-182,444-

465

3,6,14Precipitation and Design Storms21/29/07

1-191Student teacher introduction, signup, schedule, grading, learning objectives, Introduction (hydrology, hydrologic cycle, watersheds, DEMs, models)

11/22/07

PAGE NO.CHAPTERLECTURENo.DATE

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TEXT BOOK

Title: Applied Hydrology

Authors: Ven T Chow, David R Maidment, Larry W Mays

Publisher: McGraw Hill

Edition: 1988

Type: Hardcover

Pages: 572

ISBN: 0070108102

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REFERENCE BOOKS

Introduction to Hydrology by Viessman, Knapp, Lewis and Harbaugh, IEP A Dun-Donnelley, 1977Dynamic Hydrology by Eagleson, McGraw Hill, 1970Hydrology for Engineers by Linsley, Kohler and Paulhus. McGraw Hill, 1987Handbook of Hydrology by David R. Maidment, McGraw Hill, 1993HEC-HMS Users Manual

http://www.hec.usace.army.mil/software/hec-hms/

Class handouts

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GRADING

20% HomeworkSubmit: 7 numbered homeworks

Will count for homework grade

Practice: several un-graded assignmentsWill not count for homework grade

Late homework will not be accepted or graded

40% Mid-Term Exam40% Final Exam

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LEARNING OBJECTIVES

1. Recognize, analyze, and solve the problems associated with the flow of rainwater on the ground surface.

2. Benefit from the instructor's practical experience (real-world perspective).

3. Apply the theoretical knowledge of surface hydrology to real world problems and projects (applied hydrology).

4. Learn how to use HEC-HMS model to solve hydrologic problems.

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COURSE WEB SITEhttp://www.eng.ysu.edu/%7Eceegr/GIS/ysuhydro/ysuhydro.htm

Numbered homeworks (in bold letters) should be submitted for 20% of the grade.

Link to download lectures

Link to download homework

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COURSE WEB SITEClick “YSU Hydrology Course” link from www.GISApplications.com

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HYDROLOGYHydrology is the science that encompasses the occurrence, distribution, movement and properties of the waters of the earth and their relationship with the environment within each phase of the hydrologic cycle. Hydrology: Science of water’s:

OccurrenceDistribution, andMovement

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HYDRAULICSThe physical science and technology of the static and dynamic behavior of fluidsThe branch of engineering that focuses on the practical problems of collecting, storing, measuring, transporting, controlling, and using water and other liquids.

Pumps, valves, siphons, spillways

It differs from Fluid mechanics, which is more theoretical and includes the study of gases as well as liquids; Hydrology, which is the study of the properties, distribution, and circulation of the Earth's water.

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HYDROLOGIC CYCLEHydrologic Cycle: The path taken by water as it travels through various media:

AtmosphereLand

OverUnder

WaterStreamsRiversLakesOceans

The hydrologic cycle is a continuous process by which water is purified by evaporation and transported from the earth's surface (including the oceans) to the atmosphere and back to the land and oceans. All of the physical, chemical and biological processes involving water as it travels through various paths in the atmosphere, over and beneath the earth's surface and through growing plants, are of interest to those who study the hydrologic cycle.

ContinuousNo beginning or end!

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HYDROLOGIC CYCLETen processes of hydrologic cycle

1. EvaporationWater evaporates from oceans and land surface to become part of atmosphere (water vapor)

2. PrecipitationWater vapor is lifted and transported in the atmosphere until it condenses and precipitates on the land or oceans

3. InterceptionPrecipitated water intercepted by vegetation

4. Overland flowPrecipitated water overflowing on ground surface

5. InfiltrationPrecipitated water infiltrated into ground

6. Subsurface flowPrecipitated water flowing through the soil near land surface

7. Surface runoff (stream flow)Precipitated water discharged to streams

8. RechargeDeep percolation to water table

9. Groundwater flowMovement of water table deeper in soil or rock strata

10. Overflow to oceansSurface and groundwater returning to oceans

Figure 1.1.1 of the Text Book

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HYDROLOGIC CYCLE

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4

2

1

6

7

8

9 10

424 - 385 = 39

61 + 39 = 100

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GLOBAL WATER BALANCEFrom Figure 1.1.1• Land

• Inflow (precipitation) = 100• Outflow = 100

• Evaporation = 61• Outflow to ocean = 39

• From surface water = 38• From groundwater = 1

• Ocean• Inflow = 424

• Precipitation on ocean = 385• Outflow from land = 39

• Outflow (evaporation) = 424• Total Precipitation = 485

• On land = 100• On ocean = 385

• Total Evaporation = 485• From land = 61• From ocean = 424

• Atmospheric moisture from oceans = 424/485 = 87.42% ≅ 90%

Question: What’s the percentage of atmospheric moisture originating from oceans?

Answer: Approximately 90%

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GLOBAL WATER BALANCE

Total water on earth• Ocean = 96.5 %• Polar ice = 1.7 %• Groundwater = 1.7 %• Surface water = 0.099 %• Atmospheric water = 0.001 %• Total = 100%

• Driving force for surface hydrology•Atmospheric water = 0.001 % = 1 in 100,000

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SURFACE HYDROLOGYSurface hydrology: Related to movement of water over the ground surface

Includes bothOverland flowStream flow

Other processes of the hydrologic cycle related to surface water are also studied:

PrecipitationEvaporationSubsurface flow (infiltration)

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WATERSHEDS• Watershed: area of land draining into a

river at a given location (outlet)• Outlet: the most downstream point on

the stream where the flow leaves the watershed and enters the river

• Sewershed: drainage area of sewer system• Watershed divide: a line dividing

• land draining towards the given stream, and

• land draining away from that stream• Manual delineation of watersheds is done

by drawing drainage divides on topographic (contour) maps, which is cumbersome

• Automatic delineation of watersheds is done using Digital Elevation Models (DEMs) and Geographic Information Systems (GIS) software

WATERSHED

OUTLET

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WATERSHED EXAMPLES

WATERSHED

WATERSHED

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DEM DATADEM = Digital Elevation Model

Digital representation of ground surface elevation

A grid of elevation points defined by X,Y coordinates

A sampled array of elevations for a number of ground positions at regularly spaced intervals.

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MANUAL METHOD DELINEATION METHODDifficult for large watersheds

Turtle Creek Watershed Near Pittsburgh: 146 mi2, 700 Subbasins

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AUTOMATIC (GIS/DEM) METHOD

Automatic delineation of watershed boundaries and streams

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LARGE WATERSHEDSDEM approach definitely better for large watersheds

Lake Erie watershed: 400 mi2 - 1,811 subbasins

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DEM ANALYSIS SOFTWARE TOOLSSoftware Vendor and Website Notes

Spatial Analyst and Hydro Extensions

ESRI, Redlands, California www.esri.com

IDRISI Clark University Worcester, Massachusettswww.clarklabs.org

ERDAS IMAGINE Leica Geosystems, Atlanta, Georgia gis.leica-geosystems.com www.erdas.com

Formerly Earth Resource Data Analysis System (ERDAS) software

TOPAZ US Department of Agriculture, Agricultural Research Service, El Reno, Oklahoma grl.ars.usda.gov/topaz/TOPAZ1.HTM

MicroDEM U.S. Naval Academy www.usna.edu/Users/oceano/pguth/website/microdem.htm

Software developed by Professor Peter Guth of the Oceanography Department

DEM3D Viewer USGS, Western Mapping Center, Menlo Park, California craterlake.wr.usgs.gov/dem3d.html

Free download, allows viewing of DEM files through a 3-dimensional perspective

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WHAT IS A MODEL?An approximate representation of reality

Example: a recipe, a model train or plane

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MODEL CLASSIFICATION1. Physical models

Scale modelsAnalog models

2. Mathematical modelsHydrologic models

Rainfall-runoff modelingWatershedsExample: US Army Corps of Engineers’ HEC-HMS software

Hydraulic modelsFlow routing in pressure pipesWater systemsExample: US EPA’s EPANET software

Hydrologic and hydraulic modelsRainfall-runoff modelingFlow routing in gravity and pressure pipes (force mains)Wastewater and stormwater systemsSewers and storm drainsExample: US EPA’s Storm Water Management Model (SWMM)

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Mathematical model: an abstract model that uses mathematical language to describe the behavior of a system. A computer program that reads user input data to provide output resultsMathematical models are used in:

Natural sciences and engineering disciplinesPhysics, biology, and civil engineering

Social sciencesEconomics, sociology and political science

Engineers, physicists, computer scientists, and economists use mathematical models most extensively.

MATHEMATICAL MODEL

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1. PhysicalScale: Reduced scale replicas of prototype

• Ex: a dam spillwayAnalog: Another physical system having properties similar to those of the prototype

• Ex: Hele-Shaw model uses the movement of a viscous fluid between two closely spaced parallel plates to model seepage in an embankment

HYDROLOGIC MODEL CLASSIFICATION

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2. Hydrologic Mathematical (Abstract) Models - Ref. Figure 1.4.1• Deterministic: Model variables have a fixed (known) value

• Make forecasts• Example: Daily evaporation models

• Stochastic: Model variables are random and described by probability distributions• Make predictions• Example: Daily precipitation models

• Lumped: hydrologic processes do not vary spatially within the watershed• Distributed: hydrologic processes vary spatially within the watershed• Steady: flow rate does not change with time• Unsteady: flow rate changes with time

HYDROLOGIC MODEL CLASSIFICATION

Figure 1.4.1 of the Text Book

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HYDROLOGIC MODEL CLASSIFICATION

Stochastic

Space-independent Space-correlated

Time-independent

Time-correlated

Time-independent

Time-correlated

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SYSTEMS CONCEPT

• System: a set of connected parts that form a whole

• Example: Hydrologic cycle can be represented as system consisting of sub-systems and components (processes)• Reference: Figure 1.2.1 (3 subsystems)• Subsystem 1: atmospheric water

• Components: precipitation, interception, transpiration, evaporation

• Subsystem 2: surface water • Components: overland flow, surface

runoff, subsurface & groundwater outflow, runoff to streams and oceans

• Subsystem 3: subsurface water • Components: infiltration, groundwater

recharge, subsurface flow, and groundwater flow

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HYDROLOGIC SYSTEM MODELS

• Problem: Some hydrologic processes are complex and may not be described with exact physical laws• Example: Variation of precipitation in space and time

• Solution: Use the systems concept to represent the process as a model

• System Model: An approximation of the actual system• Input: measurable watershed parameters• Output: measurable hydrologic variables• Transfer Function: equation(s) that transforms input into output

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HYDROLOGIC SYSTEM

• A hydrologic system is defined as a structure or volume in space, surrounded by a boundary, that:• accepts water and other inputs, • operates on them internally, and • produces them as outputs.• Example: Figure 1.2.2

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MODEL EXAMPLES• Example 1: Watershed rainfall-runoff process as a

hydrologic system• Model Q(t) = Ω . I(t)• I (t) = model input (rainfall) at time t• Q (t) = model output (runoff) at time t• Ω = transfer function (omega)

OPERATORΩ

INPUTI(t)

OUTPUTQ(t)

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MODEL EXAMPLES• Example 2: Storm Water Management Model (SWMM)

• A hydrologic and hydraulic model• Wastewater and stormwater systems

SWMM MODEL OF A SEWERSHEDSewershed hydrologic and hydraulic modeling

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• Example 3: Rational Method Q = CIA• Used for estimating flow in sewer pipesfor designing sewer pipes

• Q = peak flow (output) • I = rainfall intensity (input)• A = drainage area (input)• C = runoff coefficient (transfer function)

• 0.97 for concrete, 0.22 for woods

MODEL EXAMPLES

Example 1:What is the peak discharge through a single culvert draining a forested watershed in Austin (TX) of 150 acres with average slope during a 10-year storm with a rainfall intensity of 6 in/hr?Q = CiAFrom Table 15.1.1, C = 0.36Q = 0.36 x 6 x 150Q = 324 cfs

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Lumped:HEC-HMS

SWMM

Distributed:Système Hydrologique Européen SHE (European Hydrological System)

A deterministic, distributed, and physically based modeling system for describing the major flow processes of the entire land phase of the hydrological cycle.

MODEL EXAMPLES SWMM

SHE

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DISTRIBUTED MODEL: MIKE SHE

Spatial and temporal variations in evapotranspiration (ET) rate

Karup (Denmark) catchment, 425 km2, single unconfined sandy aquifer

Evapotranspiration strongly depends on development stage of crops and depth to groundwater table

Additional info: Danish Hydraulic Institute (DHI), www.dhigroup.com

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HOMEWORK No. 1Watershed Delineation

• Download the USGS topographic map (bullrun.pdf) for Lewisburg, Pennsylvania

• Print the map on a color printer• Draw the watershed boundary for Bull Run by

connecting the high elevation points (ridges)• Watershed should be tributary to where Bull Run

meets West Branch Susquehanna River

• Submit topo map with watershed boundary drawn

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TOPO MAP

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HINT: DEM RESULTS

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HINT: GIS RESULTS

BULL RUN

OUTLET