# Hydrology Lab #1 Units.

## Units:
Just as hydrology has taken concepts from many fields and languages, the units
used in hydrology come from many sources.

## It is common practice in the USA to use both
metric and U.S. units.

# Volume:

## A
liter is 1 cubic decimeter hence there are 1,000 liters in a cubic meter. A
liter at STP weighs 1 kilogram or 2.205 pounds. There are 3.79 liters in a
gallon.

## A gallon contains the amount of ale the king
could drink at a single sitting and
weighs 8.33 pounds.

# The *cubic foot*

## **C**ontains
7.480 gallons is also a unit of measure of volume of water and weighs 62.31 pounds.

## Cubic
feet per second (CFS) is a common unit of flow.

# How thirsty are you?

## The
average person needs something like 1-2 quarts of water a day,
although consumption could be much higher in hot arid areas.

## Or
during fraternity parties (of beer anyway)

## Gallons
are therefore good units for individual water consumption.

# How thirsty is your toilet?

## The
typical consumption of water in residential settings is closer to 100 gallons
per day per person.

## Thus
gallons is not a very convenient unit for measuring municipal water use.

# How thirsty is your cotton crop?

## Agriculture
consumes far more water than municipal uses, so gallons are rarely used for
measuring agricultural water use.

# Acre Feet:

## Rather the *acre foot* is the
common measure for large quantities of water and is approximately 325,851
gallons.

## This
is the volume of water that will cover one acre of land to the depth of one
foot. It is equal to 43,560 cubic feet of water.

# Calculation I. Is water cheaper than dirt:

## Many
farmers pay as little as $5 per acre foot for water delivered from federal
water projects to their farms. How many pounds of water does a farmer get for a
dollar

# Cost per pound.

## 1
acre equals 43,560 square feet, 1 acre foot equals 43,560 cubic feet of
water, a cubic foot of water weighs
62.31 pounds so an acre foot weighs 2,714223.6 pounds.

## That
works out to 542,844 pounds of water delivered for a dollar.

# Dirt Cheap?

## Compare
that to dirt which for top soil would run about $5 per cubic yard (which would
weigh about 2,600 pounds) plus another $3 per cubic yard for delivery. So this
works out to about 325 pounds of dirt for $1 delivered.

## So
dirt costs over 1,600 times as much as water per pound delivered.

# Calculation II. What do you pay for water?

## In
Huntsville today the rate for the first 0-3,000 gallons is $10.65. Then the
rate is $1.80 per thousand gallons.

## Ignoring
the initial fixed fees this works out to 555.56 gallons per dollar or
alternatively $.002 per gallon.

# If farmers paid what you do:

## Therefore
an acre foot would cost: 325,851 gal -3000 gal or 322,851 gal at $.002 per gal
or $645.70 plus $10.65 for the first 3,000 gallons or $656.35 per acre foot.

## This
is more than 100 times what many farmers pay for water.

# Example III. Residential consumption.

## A
typical residential suburban family (i.e. has a lawn) uses about 1/3 of an acre
foot of water per year, about 75% for
landscaping.

## A
typical alfalfa farmer uses 5-7 acre feet of water per acre per year and will
farm perhaps 640 acres.

## That
would be equivalent to the water used by a typical town of about 10,000 people.

# Calculation.

## 180
Gallons per day X 365 days = 65,700 gallons per year.

## 6
Acre feet X 640 acres = 3,840 acre feet per year X 329,250 gallons per acre
foot =12,3360,000 gallons/ 65,700 gallons per family

## 19,229
families..

##

# Example IV:

##
The Mirage/Treasure
Island Hotel in Las Vegas employs 7,000 people and generates about $500 million
in revenues each year, it consumes 300 acre feet of fresh water per year (it
recycles its water for landscape irrigation).

##
The average small farmer
in Nevada that is growing an irrigated crop such as hay or alfalfa uses 2-10
times more water to support himself,
his family and some migrant labor.

# Units of Flow:

## After
measures of volume, measures of flow are most important in hydrology.

# CFS:

## The
important measures of flow are *Cubic foot per second (CFS)* (which
is used for streams and rivers).

## A
small stream might be 1-10 CFS a large river 100,000 or more CFS.

# GPM:

## *Gallons
per minute (GPM)* is the typical unit for production from wells. A
typical well will product 20-100 GPM while very large wells will produce 2000
or more GPM.

*MGD:*

## *Millions
of gallons per day (MGD)* is a typical unit for water treatment plants
and sewage treatment plants. A small plant might be 1-10 MGD while a large
plant might be 100-200 MGD.

*CMS:*

## *Cubic
meters per second* is not as common in the U.S. but is common everywhere
else.

# Example V Flow in Harmon Creek

## Harmon Creek has an average flow something
like 10 CFS.

## How
many gallons is this in a second? A day
or a year?:

# Calculation:

## 7.48
gal/cf x 10 cfs =

## 74.8
gallons per second.

## Per
day 60 sec/min x 60 min/hr x 24hr/day = 6,462,720 per day.

## x
365 days per year = 2,358,892,800 gallons per year.

# How much does this water weigh?

## At
8.33 pounds per gallon this is:

## 1,9,649,577,024
pounds.

# Creek for sale?

## If
I could own the flow in this creek and sell it in Huntsville at the Cities
rate what would it be worth?

## 2,358,892,800
gallons / 325,851 acre-feet/gal x $656.35/acre-foot =

## =$4,751,433.29.

# Other units

## Units
of water velocity are feet/sec or meters/sec and

## Units
of *stage* height are feet or meters.

## There
are also units of concentration, typically parts per million PPM or parts per
billion PPB.

# Specific gravity

## It
is the density of a substance relative to the density of water:

## Water
has a specific gravity of 1, solid rock and the particle matter in soil
typically has a specific gravity of 2.65, Gasoline has a specific gravity of
.75, PCB have a specific gravity of 1.6.

# Example VI: Toxic transformers.

##
A transformer with
hazardous waste PCBs inside it:

##
Concentration of 480,000
ppm of PCB s and the other material is mineral oil with a specific gravity of
approximately .8. Volume of transformer is 900 gallon and it is 100 % full.

##
EPA wants to know what
is the weight in Kg of hazardous waste shipment?

# Toxic calculation.

## ((1.6
x .48) + (.8 x .52)) 900 gal x 8.33Ibs/gal/2.205 lbs/kg.

## (.77
+ .42) 1.19 x 900 gal. 1,071 x 8.33 =
8,921.43/2.205 = 4,046 kilograms.

# Conversions:

## You
should be reasonably able to convert between these units, since some exam
problems will involve calculations where you need to make simple unit
conversions (with supplied conversion factors).

# CONVERSION FACTORS:

## **Distance:**

## 1
meter = 3.281 feet.

## 1
mile = 5280 feet

## 1
kilometer = 1,000 meters = 1,000,000 mm.

**Volume**

## 1
cubic meter = 264.2 gallons.

## 1
cubic foot = 7.48 gallons, 28.32 liters.

## 1
liter = .2642 gallons.

## 1
acre foot = 325,851 gallons.

**Flow**

## 1
cubic meter per second = 35.32 cubic feet per second

## 1
cubic foot per second for 1 day = 1.98
acre feet.

**Conversion factors metric to U.S. customary**

## 1
hectare = 2.471 acres, 10,000 square meters.

## 1
acre = 43,560 square feet.

**Weight:**

## 1
kg = 2.205 pounds.

## 1
cubic decimeter = 1 kg.

## 1
gallon = 8.33 pounds

## 1
cubic foot = 62.31 pounds

**Velocity:**

## 1
meter/sec = 2.237 mi/hr.

## 1
foot/sec = 1.097 km/hr.

**Other factors.**

## 1
inch of run-off per hour from one acre = 1 cubic foot per second of flow.