Water system analysis and relation with gutter guards

Water catchment systems and
water conservation
or, Saving Your Liquid Assets
Joe Brown, PhD
University of Alabama
New College
Southern Sustainable Agriculture Working Group
January 16-19 2008 | Louisville, KY

Rainfall: there ain’t any
• Increasing climatic variability
• More frequent and severe droughts in SE
region
– Alabama in particular
• Farmers in the region must look at water
as a scarce resource
• Conservation is the name of the game

From the oracle (NOAA climate
prediction center)
• The forecast continues to indicate persisting drought
across the Southeast through March 2008, with the
odds favoring expansion into Florida and southeastern
Georgia.
• Precipitation totals for 2007 were around 15 inches
below normal in many of the exceptional drought
areas that stretched across portions of Alabama,
Georgia, and the Carolinas.
• Despite recent rainfall, the ongoing La Niña is expected
to bring abnormally mild and dry weather to the region for
most of the winter.
• In contrast, at least some degree of improvement is
expected from Tennessee and Kentucky northeastward
through the middle Atlantic states, including some areas
of exceptional drought in the central and western
stretches of this region.

Outline
• Designing a rainwater catchment system for
domestic or garden use
• Landscape and pond design
• Irrigation: reducing losses
• Managing crops to get the most out of your water
• Other tips and tricks
• Advantages: saving water, saving money
• Advantages: protecting water quality
• Advantages: marketing
• Other advantages
• Tools and resources to improve water efficiency on
the farm

Rainwater catchment
• But, I thought we were talking about not having
any rain?
• Well, we still have rain, but it comes in less
frequent bursts – more variability
– Still plenty more than out West, so stop complaining
already – you’ve had it so good for so long!
• Capturing it is the key
• Basic rainwater catchment: roof improvements,
foul flush system, and storage

A few calculations, first
• Calculating potential supply
• Calculating demand
• Sizing the storage tank
• Sizing the foul flush system
• Costing the system

Potential supply
• Use rainfall data to calculate total volume
– One inch of rainfall X dripline area of roof =
volume of water for a one inch rainfall event
• Loss factor: multiply total volume by 0.8
– Depends on the roof material and how well
your gutter system is functioning
• Look at monthly data to make calculations

For example: during an extreme,
unprecedented drought (36 in/yr)
• 4 inches of rainfall per month
• Roof dripline area is 1000 ft2
• 0.333 ft * 1000 ft2
= 333 ft3
• 1 ft3
= 7.48 gallons
• 7.48 gallons per ft3
* 333 ft3
= 2491 gallons
per month
• Times 0.8 to account for losses = 1993
gallons

For example, during a “normal” to
wet year (60 in/yr)
• 5 inches of rainfall per month
• Roof dripline area is 1000 ft2
• 0.42 ft * 1000 ft2
= 420 ft3
• 1 ft3
= 7.48 gallons
• 7.48 gallons per ft3
* 420 ft3
= 3142 gallons
per month
• Times 0.8 to account for losses = 2513
gallons

Sizing the tank
• Say we split the difference and say 2200
gallons per month
• That equals about 75 gallons per day
• More than enough for domestic use for a
conservation-minded family
• Small garden plot use

Demand
• How much
water do you
anticipate
using?
• 100 liters per
day? 200?

Sizing the storage tank
• Where supply meets demand
• Major determinant of cost

Sizing the foul-flush system
• Volume = 1% of maximum rainfall event

• The key to choosing building materials for all parts of a rainwater harvesting
system is to select materials that are non toxic and inert (non leaching.) This
is particularly true of the roof that is subject to the oxidizing affects of sun
and air borne pollutants. Avoid such contamination sources as lead
flashings around sky lights or plumbing vents.
• Water quality from different roof catchments is a function of the type of roof
material, climate conditions, and surrounding environment. When choosing
a roofing material - the smoother the better. The quantity of rainwater that
can be collected is also a function of roof texture.
• he most common type of roofing material used for rain catchment in British
Columbia is galvanized metal that has been painted or enameled with a
non-toxic material. Other materials include slate, terracotta tiles or concrete.
Asphalt shingles are adequate but produce less water in summer and are
harder to keep clean. Beware of the "modern" shingles that contain moss
inhibitors if you plan to drink or bathe in the water.
• Water collected from cedar roofs is acidic for plants and is impractical for
indoor use.
Roof materials

Gutters
• Gutters should be made of inert materials. The most common
gutters are continuous, baked aluminum gutters made and installed
on site. Half-round vinyl is also excellent.
• Bamboo can be a good choice for you DIYers if a bit difficult to work
with for the uninitiated
• When installing gutters make sure that there is a continuous slope
towards the downspouts, and that there is no impediment to slow
the flow of debris into the downspouts. Areas where the water can
pool collect insects, organic materials and bacteria. Think of a gutter
as a river - not a wetlands or swamp.
• The decision to use gutter guard depends on the landscape and the
number and type of shedding trees in the area. It keeps some debris
out, but it also protects the debris that collects in the gutter, from the
sanitizing and self cleaning of sun and wind.

Downspouts
• Anything from chains to traditional
aluminum downspouts can be used to get
the water down from the gutters
• Sealed PVC piping is often used close to
the ground, and where the water needs to
be transported horizontally. This piping
must be sized for good flows, storm
events, and easy cleaning.

Debris traps
• The Rainwater Connection believes that a series of
debris traps and filters and necessary to clean the water
as much as possible before it enters storage. For
agricultural water a small leaf trap and cleanable pipe
systems to catch the larger heavier debris may be all
that is required.
• For potable water systems a series of leaf and debris
traps are used as the first step - leaf traps to capture the
leaves, needles and berries, and pipe "pigtails" collect
the heavier black debris.
• The Rainwater Collection has developed several types of
debris traps that work well in local conditions.

First flush
• The first flush diverter routes the first flow of water from the catchment surface away
from the storage tank. It is designed to fill with contaminated water from a rain event
and empty itself over a 24 hour period so that it is ready for the next time it rains This
system is used in most parts of the world to improve water quality for potable water
systems.
• First flush diverters ("FFD'S") have been shown to remove up to 80% of the pollutants
that collect on the roof or in the gutters and become dissolved or suspended in the
water. For example, it removes much of the discolouration and acidity from contact
with cedar, arbutus and fir needle debris.
• The amount of water to reject depends on a variety of factors including:
• Roof and gutter slope
• Roof material smoothness
• Rain intensity
• Preceding dry period
• Airborne pollutants (dust, smoke, auto exhaust)
• Tree debris
• The rainwater Connection recommends rejecting at least the first 0.02 inch (0.5mm)
of rain. This amounts to 10.4 imp gal per 1,000 sq ft of catchment area or 50 litres per
100m2. In extreme cases this is increased to as much as the first 0.04 or 1/25th inch.

Water storage
• The key
• Storage tanks/cisterns take many forms
and vary greatly by cost, volume, and
materials
• The most common storage tanks in the
US are the above ground molded
polyethylene tanks (300 - 3,000 gallons)
• Ferrocement tanks are widely used
elsewhere as well as historically in the US

Extras
• Treatment for potable use (usually not
recommended)
• Use in ‘greywater’ system

Other considerations
• Maintenance
• Treatment for potable use

Water, water everywhere
(but not on my farm)
• Limiting the farming enterprise: land,
energy, time, money, and WATER

Marketing opportunities
• Touting drought resistant or low-water crops
• Highlighting sustainable water use on the
farm
• Focus on farm impacts on water
– Well-managed agricultural land provides for
infiltration
– Erosion controls and BMPs for reduction of
runoff and therefore waterborne pollution
• Watershed, riparian zone, or wetland
protection

Drought resistance and cover crops
• Sudan sudex is best
– One sees sorghum and millet planted together in
many dry places around the world
– Sudan grass is not a legume, no nitrogen fixation
• Hairy vetch is moderately drought resistant
• Cowpeas (iron and clay peas) moderately
drought resistant
• Crimson clover is not drought resistant
• I don’t recommend kudzu, although it is drought
resistant!

• A good response to longer periods of dryness broken by
more violent rainstorms is to make your soil drought-
resistant. What you want is a way for your valuable
plants to survive a temporary water deficit, without
having to use a lot of water and perhaps pay a fine to
your municipality. So, make sure that the water from a
deluge doesn't run off. Make the water percolate down to
plants' roots. Don't till the soil; bare plowed soil loses
water to evaporation. Leave organic material lying on the
soil surface or plant groundcover (a cover crop like
clover or alfalfa in the case of farmers). Midwestern
farmers are now leaving corn plants up after harvest to
catch the snow and protect the soil. Encourage worms,
whose tunnels, about the diameter of a pencil, direct
water down to root level.

• Plants are, in a sense, cannibals. They thrive when they have partially
decomposed plant material—little bits of bark or crumbly leaves—to
consume. (Though they'll also happily take up the minerals in decomposed
animal material.) Little bits of bark or crumbly leaves work like sponges,
holding moisture in the soil. Humus, the name for that decomposing stuff, is
sort of like exercise, which can make fat people thinner and thin people
more rounded. It improves both sandy soils and clay soils, increasing the
water-holding capacity of sand and water penetration in clay. Some of the
boosters of arid-region plants have insufficiently stressed that in a garden
with heavy clay soil that doesn't drain well, or where water fails to percolate,
drought-tolerant plants will suffer in times of average rain.
• The cheering news is that perennials on the whole are drought-resistant
once their roots have developed well; they may flower less in dry conditions,
but they're in it for the long haul. Annuals panic and go to seed, hoping their
offspring will find moister conditions next year.

• Perennials, even the prairie and desert ones, do have to be watered
thoroughly when they're planted. Last weekend I saw a woman
filling the back of her station wagon with about a dozen achillea (aka
yarrow, often first on the list of drought-tolerant plants) with lovely
terra-cotta colored flowers.
• "So, I don't have to water these at all, right?" she called in parting to
the nurseryman, who kind of nodded as he moved on to another
customer. I suppose it's a good thing that I restrained myself from
running after her car, yelling that newly planted perennials don't
have a big root system, that they need a lot of water at planting time
and attentive watering through the first year until their roots have
matured and spread out. It's a complex message to get across while
appearing to be a deranged person running down the road.

• The achilleas at the home of the woman at the nursery
may well be wilting right now, their nice ferny gray leaves
sagging limply; she may be considering calling the
nursery and asking for replacements. Roots have a hard
time making contact with dry soil; watering at planting
makes the soil stick to the roots and gets rid of air
pockets where a root might dangle. Here is a gift to
Scrabble players, a word likely to be mocked and
challenged—turgor. To exhibit turgor means to be in a
state of distension. From the Latin turgidus, swollen,
inflated. (From which we have derived the idea of turgid
prose—inflated and, thus, pompous.)

• When the roots encounter a dry place, a
hormonal message travels to the leaves to close
their pores to slow down water loss. The pores,
called stomata, are usually on the underside of
the leaf. Squash and cucumber plants, which
have pores on both sides, are extremely
sensitive to lack of water; veteran vegetable
growers use them as the canaries in the coal
mine. Plants owe their capacity to be erect to
water pressure; with less water in the system,
they grow limp.

• Which takes us to a much bigger picture. Scientists are working to
make food crops that aren't adapted to arid places better at
surviving drought by making their roots more efficient. A team of
scientists headed by Roberto A. Gaxiola at the University of
Connecticut has discovered a way to manipulate plant genes to
increase root proliferation. Many naturally drought-resistant plants,
especially the grasses of our great prairies, develop deep and
dense root systems. It's a new idea; roots haven't previously been
targeted in genetic engineering. Deeper, wider roots can spread out
to more territory in search of water. The point, Gaxiola said, is to
help agriculture in arid regions—Pakistan, Africa, China, and his
native Mexico, not to mention Alabama.
• In the past we've coddled our crop plants, giving them lots of
fertilizer and water, things we used to think were unlimited. Gaxiola
is aware that not everyone is on board with the manipulation of plant
genes: "We are the witches of our time. People who don't
understand the science would like to burn us."

• Sprinkler evaporation loss can be reduced by changing sprinkler
operating conditions to increase water droplet size or by operating
the system under conditions of low climate demand. Climate
demand is low at night and during early morning and early evening
hours.
• Evaporation loss can be increased by using small nozzles and
operating sprinklers at high pressures to produce small water
droplets, and by operating systems when climate demand is
greatest. Climate demand will normally be greatest during the early
afternoon, when relative humidity is lowest and air temperature and
wind speed are highest. Sprinklers should not be operated outside
the manufacturer's recommended pressure range because they
may perform poorly under such conditions.

Trees
• Mature trees in peak summer heat can
use 250 gallons a day
• Roots may go out horizontally as far as
the height of the tree

Economics
• The allocation of scarce resources
• Creating a water balance for your farm
(exercise)

Selecting a pond site
• “Put it over yunder” has not been a
successful philosophical viewpoint or
modus operandi
• Several factors to consider, including:
– Safety
– Soils
– Geology
– Topography
– Irrigation access & proximity to crops

Factors to consider when siting
your pond: safety
• Visualize dam failure: it could happen
• Locate and identify underground utilities
• Think about recreational uses and
potential for accidents
– You may be liable in the case of injury or
death resulting from use of your pond whether
you authorized such use or not
• Identify and reduce hazards: stumps,
uncovered drains, debris, etc.

your pond: soils
• Good news for that cursed clayey soil of yours!
• Soil should contain a layer that is impervious and thick
enough (usually a 2-foot minimum) to prevent excessive
seepage
– Clay and silt/clay are fine: sandy soils are not
– Highly variable soils
• May need to cover and compact a part of a proposed
site with suitable material
– More compaction can help less-than-perfect soils retain water
– Liners are expensive but can be used for small ponds
• Leaky ponds are difficult and expensive to fix – better to
think ahead!
• Soil under the dam is particularly critical

your pond: geology
• Can seriously limit the success of your
pond
• Limestone areas may have underground
sinkholes or other formations that can
drain your pond
• Look around you: are there lots of other
farm ponds in the vicinity
– Google Earth may help you figure this one out

your pond: topography
• The “lay of the land”
• Most important factor in cost
– Locate your dam where you’ll need the least earthwork
• Location location location: locate your pond where the largest
storage volume can be obtained with the least amount of earth
moving
• Look to create the pond where you’ll be able to establish a deep
basin
– E.g., where a dam can be built between two ridges crossing a narrow
section of a valley that is immediately downstream of a broad section of
valley
– Don’t want shallow areas
• Excavated ponds are the most expensive to construct per volume of
water stored
– Aboveground water storage behind an earthen dam is always better for
your money

Your watershed
• For ponds in which surface runoff is the
main source of water, the contributing
drainage area, or watershed, must be
large enough to fill and maintain adequate
water in the pond during droughts.
– However, the drainage area should not be so
large that expensive overflow structures are
needed to bypass excess runoff during storms

Watershed
• For ponds in which surface runoff is the main source of water, the
contributing drainage area, or watershed, must be large enough to fill and
maintain adequate water in the pond during droughts. However, the
drainage area should not be so large that expensive overflow structures are
needed to bypass excess runoff during storms.
• Some characteristics of a watershed that directly affect the yield of water are
the slope of the land, soil infiltration, and plant cover. These interrelated
factors are variable and site-specific. There are no set rules for determining
the exact size watershed needed to fill and maintain a given size pond.
However, there are some rules of thumb that can be used. For example,
some watersheds containing mostly pasture with heavy clay soils may need
only 5 acres of land for each surface acre of water. At the opposite extreme,
a sandy watershed in a wooded area may need 30 acres or more of land to
contribute runoff for each surface acre of ponded water.
• If the drainage area is too small in relation to the pond size, the pond may
not adequately fill, or the water level may drop too low during extended
periods of hot, dry weather. Shallow water contributes to excessive aquatic
weed problems and potentially to fish kills from low dissolved oxygen when
average depth is less than 3 feet.

Watershed
• Ponds with excessive drainage areas can be difficult to manage for fish
production. They tend to be muddy, silt-in rapidly, and have erosion
problems in the spillway area. Runoff from oversized drainage areas can
flush out much of the microscopic plant and animal life that form the base of
the food chain for fish, thus lowering pond productivity. Fish may also leave
the pond during overflow from heavy rains. Contamination of ponds with wild
fish from either upstream or downstream sources is more likely when
watershed size is excessive.
• To avoid potential pollution of pond water, select a location where drainage
from farmsteads, feedlots, sewage lines, dumps, industrial and urban sites,
and other similar areas does not reach the pond.
• In order for the planned depth and capacity of a pond to be maintained, the
inflow must be reasonably free of silt from an eroding watershed. The best
protection is adequate erosion control on the contributing drainage area.
Land under permanent cover of trees or grasses is the most desirable
drainage area. If such land is not available, treat the watershed with proper
conservation practices to control erosion before constructing the pond.

Pond sizing
• The size of an embankment pond should be relative to the size of the watershed
(drainage area) contributing runoff to the site. Ponds with too little watershed will have
difficulty filling up and remaining full during drought conditions, and ponds with too
much watershed require expensive water control structures and are difficult to
manage (see Watershed/Drainage Area).
• To ensure a permanent water supply, the water in the pond must be deep enough to
meet the intended use requirements and to offset probable seepage and evaporation
losses. The minimum recommended depth of water for ponds in Alabama is 6 to 7
feet. Greater minimum depths are needed for ponds in which a permanent or year-
round water supply is essential, such as for irrigation or fire fighting, or where
seepage is more than normal. Most typical farm ponds in Alabama have 10 to 15 feet
of water at the dam.
• The estimated capacity, or volume, of the pond can be determined by multiplying the
surface area of the pond in acres by 0.4 times the maximum water depth in feet
measured at the dam. For example, a pond with a surface area of 3.2 acres and a
depth of 12.5 feet at the dam has an approximate capacity of 16 acre-feet (0.4 x 3.2 x
12.5 = 16 acre-feet); (1 acre-foot = 325,851 gallons). An exact capacity of the pond
can be obtained only through detailed surveys and calculations.

Calculate pond volume
• Formula
• Acre feet gallon conversion

Water quality issues
• For irrigation, you’re mainly concerned
with the solids content
– Turbidity, Total Suspended Solids, Total
Dissolved Solids
• Consider a granular filtration unit
– Rapid sand filter
– Roughing filters, slow sand filters, others
• Locating the intake to reduce solids
content

Sources for your pond water: rain
• The primary source of water for embankment ponds is rainfall runoff
from the drainage or watershed area surrounding the pond. Rainfall
runoff can be an excellent "free" source of water, depending on the
physical and chemical characteristics of the watershed. The best
runoff water source for ponds is a watershed containing
undisturbed, well-vegetated cover such as timberland or grassland.
Unvegetated watersheds should be avoided because of the
potential for excessive muddiness and premature siltation of the
pond. Watersheds containing concentrated livestock feeding areas
or overfertilized pastures can result in problems due to excessive
nutrients and other contaminants entering the pond. Watersheds
with cropland receiving regular pesticide applications are of concern
because of the potential for pond contamination from runoff or spray
drift. Ponds receiving runoff from cropland should have a good
buffer zone of grass or sod between the cropland and the pond to
serve as a filter for potential soil erosion and pesticide runoff.

Sources for your pond water:
springs or other surface water
• Surface water from nearby springs,
streams, rivers, or reservoirs that have
good water quality can be used as a pond
water source
• How reliable is it? What’s the flow rate?
• Pumped groundwater: maybe not such a
good source

Photo of our surface water sourced
pond

Assistance…
• For small ponds, the Natural Resources Conservation
Service (NRCS) in Alabama may provide free planning,
design, and construction assistance to private
landowners in the state. The NRCS has been the
recognized expert in this area for over 60 years.
However, due to workload and workforce, the NRCS in
some counties may only provide limited assistance on
ponds. Private consultants (professional engineers) are
available to provide this assistance for a fee.
• “Sometimes government agencies will share the cost
through watershed restoration and conservation projects
ask about local programs. Just be aware of any strings
attached, such as a requirement that your pond be kept
open to the public. “

Purr-mitting: covering your liquid
assets
• Good pond sites will sometimes include land areas classified as wetlands.
– Wetlands include marshes, swamps, and shallow areas that pool water
seasonally and support wetland-type plants such as bulrush, cattails, cypress
trees, etc.
• If wetlands are present on a pond site, they must be identified before
construction of the pond. Federal wetland programs such as Section 404 of
the Clean Water Act and Swampbuster provisions of the Food Security Act
may apply to private landowners who construct ponds in areas considered
to be wetlands. Always check with the U.S. Army Corps of Engineers or the
USDA Natural Resources Conservation Service (NRCS) before construction
to determine which specific law or regulation may apply to you. In some
cases, it may be necessary to obtain a permit or additional planning
assistance.
• If wetlands are present (depending on the type and amount), locating an
alternative pond site without significant wetlands may be the best
alternative. That way, paperwork and possible litigation can be avoided and,
most importantly, the wetland and its benefits to the environment will be
preserved.

Permitting
• Legal Issues. In the past, property owners could dig a
pond anywhere on their land, and many people
constructed ponds in wetland areas low-lying spots that
already collected water. But more recently, the public
has realized the value of wetlands for wildlife habitat and
maintaining water quality, so there now are regulations
that limit where you can put a farm pond.
• If you construct a pond without acquiring the proper
permits, you could find yourself in court, faced with
heavy fines and huge wetland-restoration bills and worse
yet, no pond. You can avoid this issue by choosing a
pond site with care and following local regulations.

Permits
• The owner must obtain any required permits before hiring a contractor. If
wetlands are involved, a permit may be required from the Corps of
Engineers.
• Pond sites that involve a total of 5 or more acres of land disturbance during
construction require a National Pollution Discharge Elimination System
(NPDES) permit issued by the State environment department.
– Will require that a Best Management Practices (BMP) plan be developed and
implemented to control erosion during construction and also requires that the
BMPs be monitored to ensure that they are working properly.
• Even if the site is smaller than 5 acres, the landowner and contractor should
make a conscious effort to control erosion during construction. A simple way
to do this is to perform no construction activities in the pool area until after
the dam is near completion. This minimizes land disturbance and creates a
basin to trap the sediment produced in the pool area. In all cases,
vegetation should be established to control erosion as soon as possible
after construction.
• Other state and local laws may apply as well.

Shaping your pond: form follows
function
• Look to maximize efficiency
• Usually the shape will follow from the landscape
• A pond constructed for the purpose of irrigation will be
better the deeper it is, since you want to minimize
surface losses due to evaporation
• A circular pond will usually hold more water with less
earthwork, all else (e.g., average depth) being equal
– “You have noticed that everything an Indian does is in a circle,
and that is because the Power of the World always works in
circles, and everything tries to be round. In the old days when
we were a strong and happy people, all our power came to us
from the sacred hoop of the nation, and so long as the hoop was
unbroken, the people flourished.”
• From Black Elk Speaks

Hiring a contractor
• Unless you have the necessary equipment, you will need to hire a contractor to build the pond. A
list of pond contractors can be obtained at your local NRCS office. You may wish to receive bids
from several contractors to be sure you are getting the best quality job done at the lowest
possible cost. It is always best to talk with others who have had ponds built. Ask for references
from your prospective contractor before finally contracting your construction project.
• Before contracting, have a set of plans and specifications prepared. The plans should show all
elevations and dimensions of the dam and emergency spillway, the dimensions and extent of the
cutoff trench and other areas requiring backfill, and the location, dimensions, and elevations of
the principal spillway, bank contours, and other planned structures. The plan should also include
a list of the quantity and kind of building materials required.
• The specifications should give all the information not shown on the plans that is necessary to
define what is to be done, prescribe how the work is to be done if such direction is required,
specify the quality of material and workmanship required, and define the method of measurement
and the unit of payment for the various items of work that constitute the whole job.
• Construction work of the quality and standards desired will not result unless there is a clear
understanding of all the requirements for the job between the owner and the contractor. For these
reasons, good plans and specifications should be prepared for all ponds for which an owner
awards a contract.
• The local Soil and Water Conservation District, the NRCS, and private consultants (professional
engineers) can assist in preparing the plans and specifications. These people can also provide
assistance during the construction phase; however, the primary responsibility to ensure that the
job is constructed according to plans and specifications is the owner's.

Site survey and layout
• Certain information for the potential pond site must be
obtained through engineering surveys. At a minimum,
information collected should include surveys for the
proposed earthen dam location, emergency spillway
location, and shoreline for the pond. Any soils
investigation should be documented and referenced to
the site survey. The information gathered from the field
surveys will then be used by the designer to calculate
the elevations and earthfill quantities associated with the
construction of the dam. Just prior to construction, the
site survey and design information is used to precisely
lay out the earthen dam and emergency spillway for
construction.

Pond types: embankment
• The most common type of pond in Alabama is the embankment pond, also called
watershed pond or hill pond (Figure 2). A watershed is the drainage area around the
pond within which rainfall drains toward the pond. A dam or embankment is
constructed in a depression between two hills and serves to impound water in a basin
area on the upstream side of the dam. This type of pond is best suited for areas with
slightly to moderately rolling topography.
• Embankment ponds usually depend on rainfall runoff to fill and then maintain water
levels. Pond size, shape, and depth are limited by the topography of the site and the
size of the watershed draining to the pond. Generally, the steeper the slope of the
pond site, the smaller the pond that can be constructed. Well-sited embankment
ponds generally require the least amount of earthmoving per acre of water
impounded compared to other types of ponds. Because construction costs are based
largely on the amount of earthmoving, an embankment pond is generally the least
expensive type of pond per surface acre of water to construct.
• Building a dam across a large, permanent stream is not a recommended practice for
constructing a pond. Following heavy rainfall, streams often carry large amounts of
suspended sediments that will settle out in the pond and severely shorten its useful
life. Ponds fed by large streams can be difficult to manage for fishing due to
competition from wild fish, the introduction of fish diseases, and the inability to
effectively fertilize the pond due to excessive outflow.

Pond types: excavated
• Excavated, or "dug," ponds are constructed
almost entirely below original ground level
(Figure 3). This construction method is usually
used only for construction of small ponds
(generally less than 1/2 acre) because of the
large amount of earthmoving required in relation
to the size of the pond. Excavated ponds may
require an external water source to fill and
maintain the pond if springs, groundwater, or
runoff are not sufficient. An excavated pond is
usually the most expensive type of pond to
construct on a per-acre basis.

Pond types: levee
• Suitable for flat or nearly flat land, levee ponds are only
partially excavated. Earth from what is to be the basin
area of the pond is removed and used to construct the
sides, or levees, of the pond that impound the water
(Figure 4). The water level in a levee pond is higher than
the original ground level. Water depth is usually similar
throughout the pond and is regulated by the height of the
outlet pipes and constructed levees. An externally
pumped water source, such as a well or creek, will be
necessary to fill and maintain this type of pond due to the
absence of a watershed. Per-acre construction costs of
levee ponds generally fall between those of watershed
and excavated ponds.

Pond types: combination
watershed-levee
• An example of a combination watershed-
levee pond would be a two- or three-sided
levee pond that connects to an existing hill
to form its other side (Figure 5).
Depending on the site, the hill side of the
pond can provide a significant amount of
watershed runoff to the pond, thus
reducing and, in some cases, eliminating
the need for pumping water to fill and
maintain the pond.

Pond construction: costs
• The cost of constructing a pond can be highly variable. On a per-acre basis, small
ponds are generally more expensive than larger ponds. Small ponds can easily range
from $10,000 to $20,000 per acre or more, while larger ponds (10 acres or more) can
range from $1,000 to $5,000 per acre or possibly even less for ideal sites. The largest
single factor controlling the cost of constructing a pond is the amount of earthmoving
required. Other costs such as clearing, site preparation, pipe, concrete, and seeding
and mulching are often only incidental compared to the earthmoving cost.
• The best way to contract the work of building the pond is to have individual unit prices
and pre-agreed-upon costs for every item to be completed in the construction of the
pond. Some pond owners elect to "lump sum" the job. That is, the contractor gives
them one price for the entire completed job. This is fine unless changes in
construction are required, in which case, modifications to the work are difficult to
price. Some contractors may want to do all or portions of the work on an hourly basis.
This could prove to be expensive since the pond owner has no control over the time
required to do the work.
• The cost of installing a pond can sometimes be cost-shared through government
programs if the pond actually reduces downstream water pollution or is used as a
source of water for livestock. Check with the local Soil and Water Conservation
District Office and the NRCS for potential cost-share money.

Reducing water losses in ponds
• Surface plants

Leaky ponds
• Excessive seepage is a common pond problem in many areas. Most severe seepage problems
can be traced back to two fundamental causes: a poor site and/or improper pond construction
practices. A poor site may be one in which either the soils are too permeable to hold water and/or
the underlying geology is not conducive to holding water. Risky geological structure includes
underlying cavernous limestone prone to develop sinkholes or exposed rock areas in the pond
bottom around which water might channel beneath the pond. Seepage rates can vary
considerably for ponds, depending on the dominant soil type. However, properly constructed
ponds on good sites will have low seepage rates. Table 1 lists relative seepage rates plus
average summertime evaporation in Alabama to show potential water level drop (assuming no
added water from rainfall, runoff, groundwater, or other sources).
• Improper pond construction techniques are often the cause of excessive seepage. As discussed
previously under Pond Construction, most embankment ponds require a cutoff and core trench
compacted with a good-quality clayey material along the centerline of the dam and extending
down into impervious material. Failure to properly install the core trench can result in excessive
seepage through the base of the dam. This problem can sometimes be corrected through
draining the pond and installing a new core trench in front of the dam.
• Proper soil moisture is very important for obtaining optimum compaction during the construction
phase. Ponds constructed with soil either too dry or too wet can result in excess seepage due to
poor compaction. Generally, the soil is too dry if it can't be molded in your hand and too wet if it
adheres to the construction equipment or is obviously saturated. There are several methods and
materials that can be used to seal leaking ponds, including compaction, clay blankets, bentonite,
chemical dispersing agents, and pond liners.

Is my pond leaking or evaporating?
Seepage Rates Showing Potential Water Level Drop
SUMMERTIME POND LEVEL DROP (inches per week)
Seepage
Rate
+ Evaporation* = Pond Water
Level Drop**
Low <1.4 + 1.0 = <2.4
Medium 1.4 to 2.75 + 1.0 = 2.4 to 3.75
High >2.75 + 1.0 = >3.75
*Evaporation averages about 1 inch per week (June-September) in full sun.
**Assuming no water entering pond (and no irrigation either)

Drilling a well
• Capitalizing on our stable past climate
• Shallow groundwater
• Deep wells: costs of drilling and operating

Build for the future
• Given the increasing trend of severe weather,
Matson says ponds need to be built better than
ever. The construction of pond dams must take
into consideration potential flood damage should
the dam or overflow-spillway channel fail. It is
even more important to build ponds with
spillways that can handle what they used to call
50- or 100-year floods, Matson says. With
continuing climate changes, you really want to
make the dams sturdy and make spillways
function properly with large water loads.

Maintenance
• Keep your pond surrounded by large grassy
areas to prevent soil from washing into the pond
from nearby fields. Also keep in mind that the
ponds own water can cause soil erosion. Wind-
whipped waves can eat away at a ponds banks,
dam and spillway. Common solutions include
breaking up waves with an obstacle such as a
floating log boom, or building rock-lined banks
called riprap which work well where the water
level fluctuates widely. Keep livestock out of
your pond as much as possible, both to prevent
erosion and to maintain water quality.

New life for old ponds
• Matson says the ideal pond is one that already exists and is maybe 20 to 30 years old and just
needs to be cleaned out. If you have an old pond site on your property, its well worth taking the
trouble to clean it up, rather than negotiating permits and incurring the expense for a new one.
(See New Life for Old Ponds, above, for more on resurrecting an old pond.)
• “Earth ponds flow naturally toward oblivion,” says pond expert Tim Matson. “Vegetation decays,
sediment accumulates and the basin erodes. Eventually, without help, the pond disappears.”
(Read Matson’s article “Maintaining Your Pond,” at www.MotherEarthNews.com.)
• Nevertheless, it is possible to revitalize an old pond. Take, for example, the experience of Keith
Crotz, a now proactive pond-keeper in central Illinois. The pond on his farm was 24 feet deep
when his late grandfather, William, built it for fishing in 1962. Thirty-five years later, the one-acre
pond was practically dead. “The pond had pretty much filled in because of poor farming
practices,” Keith says. “The silt came off of our land, which was plowed, disked and harrowed,
regardless of the weather. In 1997, we dredged out about 20 feet of silt, rebuilt the dike and put in
a new drain and overflow.”
• Crotz still raises corn, soybeans and wheat on the farm that has been in his family since the
1860s, but he no longer worries about soil erosion filling his pond. “Now that we’re no-till and
organic, we don’t have those problems.” A 100-foot-wide grass buffer also encircles his pond.
The U.S. Department of Agriculture picked up most of the cost for reviving the pond as part of a
watershed-protection program; Crotz had to pay for only 20 percent of the project’s total cost.
• Now the reborn pond is full of bass, bluegill and bullfrogs, and attracts a variety of other wildlife.
With an electric pump, the pond keeps a livestock water tank filled and provides plenty of
irrigation water for a one-acre market garden.

Wells
• Deep wells are effectively a non-renewable resource
– Expensive to drill, uncertainty of where to drill
– You pay by the foot, usually with a minimum charge (not
including pumps, plumbing, electrical work, etc.
• Shallow wells may experience water quality issues, but
are generally suitable for irrigation uses
– Not always available
– Your land use will influence recharge
• Both are subject to drawdown and depletion when you
need it least!
• Both can be expensive to operate and maintain
• Yield can vary widely: estimate your needs
– Both domestic AND agricultural?

Wells and water quality
• Low solids: that’s good
• Shallow wells may be subject to fecal
contamination
– 100% of septic systems fail at some point
• Potential for pesticides: national survey in
1992 detected presence of pesticides in
4.2% of all rural domestic wells (probably
a low figure)

Water conservation on the small
farm
• Irrigation: reducing losses
• Managing crops to get the most out of
your water

Irrigation
• “North Carolina is located in a humid
region where irrigation must be planned in
conjunction with prevailing rainfall
conditions. In humid regions such as ours,
applying routine amounts of irrigation
water at regular intervals will almost
always result in overirrigation and the
needless waste of water and energy”
– Evans, Sneed, and Cassell (1996) NCCES

Being stingy with your water by
asking the tough questions

Checking soil moisture
• The “feel method”

Moisture
Deficiency
Inches/ft
Coarse
(Loamy Sand)
Light
(Sandy Loam)
Medium
(Loam)
Fine
(Clay
Loam)
Moisture
Deficiency
Inches/ft
(Field Capacity) (Field Capacity) (Field Capacity) (Field Capacity)

0.0
Leaves a wet
outline on hand
when squeezed

Leaves a wet outline
on hand when
squeezed; makes a
short ribbon
Leaves a wet outline
on hand when
squeezed; will ribbon
out about 1 inch
Leaves a wet
outline on hand
when squeezed;
will ribbon out
about 2 inches

0.0
0.2
Appears moist

Makes a hard ball
      0.2
0.4
   Makes a weak ball
   Forms a plastic ball,
Slicks when rubbed
Will slick and
ribbon easily
0.4
0.6

Sticks together
slightly

Makes a good ball.



Makes a thick
ribbon
Slicks when
rubbed
0.6

0.8 Very dry; loose,
flows through
fingers


Makes a weak ball
Forms a hard ball    0.8

Makes a good
ball
1.0

Wilting point


Sticks together

Forms a good ball
  Will ball but
won’t flatten
rather than
crumble
1.0

Irrigation scheduling
• Delivering the correct amount of water at
the correct time
• Know your crops’ water sensitivity and
needs at various stages of growth
• Monitor soil moisture, even if it’s just
through spot checking with the feel test

Weeds and trees
• Compete with your plants for water

If you can, scale back
• Reduce area planted: no use trying to stretch too
little water over too little land – you run the risk
of overstressing everything
• Reduce production of water intensive crops if
you can
• Focus on giving adequate water to those most
critical ($) crops and cut corners on the “extras”
that may not be as marketable
• Hard choices are sometimes needed

Crop selection
• Certain crops and varieties are less
sensitive to water stress
– May not be as productive
– May not have as high a market demand
• Talk to your extension agent

Water and your soil
• Soil type and structure is a major determinant of how
much water is held and whether your crops can access it
– E.g., clay holds a great deal of water, but that water may not be
easily accessible to plants
• Soils that are too sandy may not hold water well at all
• You can promote water infiltration, retention, and
accessibility by developing proper soil structure and
fertility
– Organic matter, cover crops (promote infiltration and reduce
evapotranspiration), etc
– Advantage of reduced tillage, no-till systems: undisturbed soil
holds water
– Worms

The obvious
• You know you’re doing something wrong
when:
– There are puddles of water hither and yon
– You see jets of water coming up between
rows, from valves, at couplings, etc
– Tiny rivers appear out of nowhere

In a drought emergency…
• Don’t prune or fertilize plants (creates
more stress)

.
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