Hydrological Cycle and
Water Budget
87-323-01: Hydrology
Winter 2009
87-323 Hydrology
University of Windsor
Definition:
Definition:
"Hydrology is the science that treats the waters
of the earth,
- their occurrence, circulation, and distribution,
di
- thei
PROBABILITY AND
STATISTICS
87-323: Hydrology
Winter 2009
87-323 Hydrology
University of Windsor
2
Statistics
To extract the essential information from a set of data, reducing
a large set of numbers to a small set of numbers
Summarizes the important charac
URBAN HYDROLOGY
87-323: Hydrology
Winter 2009
Could be storm sewer
or combined sewers
Designed to handle a peak
flow corresponding to a given
return period
2 10 year for
suburban drains
10-50 year for
major highways
major highways
87-521 Hydrology
Univers
SWMM
Storm Water Management Model
To simulate the runoff of a urban drainage basin for
any prescribed rainfall pattern
Performs event and continuous simulation
event and continuous simulation
recent continuous version keeps track of long-term water
budge
HYDROLOGICAL MODELING
87-521: Hydrology
Fall 2008
Modeling
Modeling
Model is
an approximation of the actual system
whose inputs and outputs are measurable
hydrological variables, and
its structure is a set of equations linking the
inputs and outputs
Syste
FLOOD ROUTING
FLOOD ROUTING
87-323: Hydrology
Winter 2009
FLOOD ROUTING
FLOOD ROUTING
A procedure to determine the time and magnitude of flow
(the flow hydrograph) at a point on a water course from
known or assumed hydrographs at one or more points
upstr
Unit Hydrograph
87-323: Hydrology
Winter 2009
6.1 DEFINITIONS AND INTRODUCTION
Concept introduced by Sherman in 1932 as follows:
If a given one-day rainfall produces a 1-inch depth of
runoff over the given drainage area, the hydrograph
showing the rates a
HYDROGRAPH
87-323: Hydrology
Winter 2009
6.1 Hydrographs
a relationship of flow rate (discharge) and time at a particular
location on a stream
Streamflow hydrograph or discharge hydrograph
hydrograph or discharge hydrograph
An integral expression of the p
Streamflow
87-323: Hydrology
Winter 2009
5.1 Watersheds and Drainage Basin
Watershed
area of land drained by surface water runoff
area of land that contributes surface runoff to any
th
point of interest
Drainage basin
area of land drained both by surface
INTERCEPTION
87-323: Hydrology
Winter 2009
3.1 INTERCEPTION
Defined as that segment of the gross precipitation which
wets and adheres to above-ground objects and
eventually evaporates
eventually evaporates
That which makes it to the ground is called throu
EVAPORATION
AND
EVAPOTRANSPIRATION
3.4 EVAPORATION AND
EVAPOTRANSPIRATION
EVAPOTRANSPIRATION
Evaporation - Movement of water from earth surface
(land and water) to atmosphere
Transpiration - Movement through plants from earth
surface to atmosphere
2/3 of
4.2.6 GREEN-AMPT MODEL
Figure 4.2.10 Definition sketch for Green-Ampt model
From Darcys law
q=K
h
l
q = fp infiltration capacity
K = Ks, i.e., Saturated hydraulic conductivity
Because as water goes in, the saturation behind the front
approaches 1.0
f p =