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...i,. .v^.*- <m» , --«ivr v -.lit. 





/^ULLYING occurs in every State in the Union. 

Besides ruining fertile land, gullies interfere 
with farm operations, undermine buildings, en- 
croach on public highways, endanger the life of 
stock, and often mar the beauty and lower the mar- 
ket value of a farm. They are also largely respon- 
sible for filling up reservoirs, streams, and dredged 
channels, and for covering bottom lands with de- 
posits of sand. 

Gullies can be prevented by increasing the ab- 
sorptive capacity of the soil, protecting the surface 
from erosion, and conducting the surplus water from 
the field at a low velocity. Gullies can be reclaimed 
by plowing-in and seeding to grass or timber, or by 
building soil-saving dams that check erosion and 
cause the gully to fill with silt above the dams. 

It is recommended that this bulletin be read in 
conjunction with Farmers' Bulletin 1669, Farm 

Washington, D. C. Issued February, 1922 

Revised February. 1932 


By C. E. Ramser, Senior Drainage Engineer, Bureau of Agricultural 




Occurrence of guliies 1 

Results of gullying 2 

Causes and types of gullies 3 

Head erosion 3 

Ditch erosion 4 

Waterfall erosion 4 

Erosion by freezing and thawing. 5 

Prevention of gullying 6 

Checking head erosion 6 

Natural control and reclamation 7 

Plowing-in and seeding gullies 8 

Tiling and plowing-in gullies 9 

Planting trees to control gullying 9 

Soii-saving dams for gullies 11 

Loose-straw dam 12 

Sod dam 12 


Wooden-stake dam 13 

Brush dam 13 

Wo von -wire dam 17 

Pole dam 18 

Log dam 19 

Willow-post dam 20 

Loose-rock dam 21 

Stone-masonry dam 22 

Concrete dam 23 

Earth dam 24 

Drop-inlet highway culverts 28 

Outlets for soil-saving dams 30 

How to reclaim a gully with soil- 
saving dams 33 

Spacing dams in a guliy 34 


GULLIES occur in every State. In the South damage to farm 
land is prevalent because the rainfall is heavy and much of the 
land has been devoted year after year to the production of row crops, 
such as cotton, corn, and tobacco. 

Figure 1. — Gully encroaching on farmer's premises which, unless controlled, wiii under- 
mine the buildings, ^ Near Alma, Wis 

Gullies are also common in the North and frequently cause serious 
damage. 2 In a typical case an 80-acre farm, on which there were no 

^u^S bulletin is based in part on studies conducted In cooperation with the Bureau of 
Chemistry and Soils. 

* For a discussion of the damage done by soil erosion see Department Circular 33, Soil 
Erosion a National Menace. 


gullies 35 years ago, has been practically ruined for farming due to 
the formation of a large gully with many branches. This gully grew 
to a depth of 15 to 20 feet and was 30 to 60 feet wide. Expensive 

concrete structures were 
required to prevent it from 
crossing two highways. 


The greatest damage 
caused by gullies is the car- 
rying away of fertile soil. 
Other bad features are : 

They can not be readily 
crossed by teams and farm 

They grow rapidly, if 
unchecked, and often ex- 
tend through a farmstead, 
undermining and neces- 
sitating the removal of 
farm buildings. (Fig. 1.) 

They encroach upon 
public highways and make 
travel unsafe. 

They extend across farm 
roads, undermine culverts 
and similar structures (fig. 
2), often necessitating the 
building of bridges. 
They cause the silting up of reservoirs and natural channels, and 
of channels dredged at great expense. (Fig. 3.) 

m 1 

Figure 2. — Road culvert and concrete drop inlet 
built at great expense to prevent gully from cross- 
ing the highway. It is shown partly undermined 
and later was washed out. Near Alma, Wis. 

Figubb 3.r**Cnannei nearly filled with sand washed from adjoining hills, requiring 
dredging at great expense to provide drainage for the' bottom lands. Gwinnett 
County, Ga. 

They carry sand washed from hills and deposit it on rich bottom 
land, making it unproductive. (Fig. 4.) 

* They give a farm an unsightly appearance, reducing its market 
value and that of adjoining farms. 

gullies; how to Contkol and reclaim them 3 

They endanger the life of stock that graze near the edges of 
undermined banks. 


Gullies are caused by erosion due to water collecting and flowing 
at a velocity sufficient to move and carry away soil particles. 

Figure 4. — Part of cornfield covered with sand washed from hillside gullies, the 
result of one heavy rain. Near Jackson, Tenn. 


When plants and soil 
are unable to retain all 
of the rain that falls on 
rolling or hilly land the 
surplus flows over the 
surface to a drainage 
channel at the foot of 
the slope. If there are 
no draws or depressions 
the water travels over 
the surface to the foot 
of the slope in broad, 
thin sheets. Where de- 
pressions exist, how- 
ever, the water from 
the surrounding area is 
collected and forms a 
stream with power to 
wash away the soil. 
The power to erode in- 
creases as the stream 
increases in size and ve- 
locity, and if the de- 
pression is not protected from erosion by grass or other means a gully 
is formed which is enlarged by each succeeding rain. 

Figure 5. — The beginning or a gully down a hillside. It 
was caused by the passing of a wagon once down the 
slope, and if not controlled, is destined soon to be a 
large gully. Near Jackson, Tenn. 



Gullies may also be started by artificial means such as the track of 
a wagon driven down a slope when the ground is soft(fig. 5), or by 
dragging a plow down a slope. Mole holes and cattle paths fre- 
quently cause the formation of gullies. One of the most common 
ways in which gullies are started is by plowing or cultivating straight 
up and down a slope. (Fig. 6.) A dead furrow extending in the 
direction of the slope may rapidly develop into a gully. 


Where head erosion occurs on the upper part of a watershed it 
makes channels for the rapid removal of the excess water from the 
field slopes and delivers the water in large volume to the natural 
drainage channels at the foot of the slopes. The capacity of these 

FiGuaB 6. — Gullies on a hillside due to running cotton rows directly up and down the 
slope. Near Jackson, Tenn. 

channels is overtaxed by the quick delivery of the water from all 
parts of their watersheds, and the result is that the channels are 
greatly enlarged by the erosive action of the water. This enlarge- 
ment continues until huge gullies are formed, often 15 to 20 or more 
feet deep. Enlargement caused by ditch erosion is very rapid on the 
upper parts of the watershed, where the slopes are comparatively 
steep. Ditch erosion generally decreases downstream as the fall of 
the channel becomes less, and the fall often becomes so slight that 
silting instead of erosion occurs, particularly where the channel 
extends across a wide bottom and discharges into another stream. 


Waterfall erosion, which is responsible for many of the deepest 
gullies or chasms, is caused by water falling over the edge of a gully 
or ditch bank. The falling water undermines the edge of the bank, 
which caves in, and the waterfall moves upstream. ^ This under- 
mining goes on rapidly, if the surface soil is underlain by sand or 
easily eroded subsoil saturated with water. 

gullies; how to control and reclaim them 


- In this manner gullies often start in the banks of natural water- 
courses which have been eroded to a great depth. They extend back 
into the land slopes and grow deeper up the slope, otten attaining 
depths of 50 to 60 feet. As they extend backward and cross tributary 
watercourses or 
natural depression, 
waterfalls are in 
turn formed in 
their sides, and 
branch gullies de- 
velop. (Fig. 7.) 
This branching 
may continue until 
a network of gul- 
lies covers the en- 
tire watershed. 
Gullies formed by 
waterfall erosion 
may extend back 
through almost 
level land. Their 
growth is depend- 
ent upon the size of 
the drainage area 
furnishing w h t e r 
and not upon the 
slope of the land. 
They sometimes 
grow at the rate of 
30 to 50 feet in a year, depending upon the amount of rainfall, the 
drainage area, and the character of the soil. 

Figure Z.— Gully branching off from main gully and advanc- 
ing up a hillside, growing in depth as it eats its way. 
Note the undermining of the bank at its head. Near 
. Alma, Wis. 

Figure 8. — Gullied area on moderate slope, growing larger each year. A type of gully- 
ing due largely to freezing and thawing, followed by heavy rains. Near MIddletown, 


Another type of erosion, common throughout the South, is caused 
by alternate freezing and thawing followed by heavy rains. It 
works on all slopes of a gully bank and does not necessarily follow 
watercourses. Owing to its ability to extend in all directions, erosion 



of this type expands over wide areas, its direction of growth not { 
being dependent upon the slopes of a field. It progresses rapidly, 
particularly in silty loams and clay loams. (Fig. 8.) 


Many large gullies would never have been formed if steps had 
been taken to check .them in the beginning. Gullies from head 
erosion could be prevented if each square foot of the field slopes 
could be made to absorb all of the rain that falls upon it. The water 
would then be fed slowly to the main water course below. Means 
employed to this end are : increasing the humus content of the soil, 
deep plowing, the use of cover crops, proper crop rotation, contour 
plowing, and tile draining. 

It is, of course, impossible to make any soil absorb all of the water 
from the heaviest rains, and in order to prevent erosion the excess 

water should be conducted 
from the field at a low velocity. 
This can be most effectively 
done by terracing the land. 
Farmers' Bulletin 1669 covers 
in detail the practice of ter- 
racing farm lands. 


•No matter what method is 
adopted for control and recla- 
mation of a gully, it is first of 
all important to check erosion 
at the head of the gully. 
Where possible it is advisable 
to intercept the water before 
it enters the head of the gully and divert it into a natural watercourse 
nearby. In shallow gullies, 3 or 4 feet deep at the upper end, head 
erosion can be checked quickly by building a low obstruction or dam 
close to the head of the gully. A fill of soil will occur between the 
dam and the head of the gully, the drop of the water will be reduced 
by the height of the dam, and the erosive and undermining action of 
the water will be greatly decreased at the head of the gully. If the 
gully is deep, a comparatively longer time will be required to fill it, 
whatever method is employed, and during the filling some temporary 
means should be employed to stop head erosion and undermining. 

One method of checking head erosion that is widely used in Iowa 
consists in placing brush and straw in the head of the gully and 
fastening it down as shown in Figure 9. Posts should be set deep in 
the ground, close to the bank of the gully, and 2 to 3 feet apart. 
Fence posts can be used. A layer of straw is first thoroughly packed 
around the posts and against the eroded and undermined part of the 
gully bank. A few branches are laid crosswise and interwoven 
between the posts to hold the straw in place. Brush is packed down 

Otrmct/on of Water* 

Figure 9. — Method of checking erosion and 
undermining at the head of a gully with 
brush and straw held firmly in place 3 

3 From Bui. 74 of the Iowa State College agricultural extension department. 

gullies; how to control and reclaim them: 


over the straw, the tops of the branches extending .nearly to the top 
of the bank, and is held in place by the crosspiece nailed to the post 
as shown in Figure 9. This affords a place on which the water will 
fall without causing erosion and stops the progress of the gully by 
preventing undermining until the gully is filled by other methods. 

In Figure 10 is shown a sheet-metal flume at the head of a gully. 
The water is conducted into the flume between earth dykes. This 
flume is intended for use until the gully can be filled by means of 
dams constructed below. Some sort of protection is generally re- 
quired at its lower end to prevent washing. 


Nature's method of controlling gullies is to prevent erosion on 
the surface by the growth of vegetation and to hold the soil together 
by the plant-root systems. The dead organic matter which accu- 
mulates on the surface of the soil from year to year prevents surface 

Figure 10. — Water conducted into head of gully by levee and a sheet-metal flume, the 
left-hand levee not yet built ; brush and stone to be placed at the lower end of the 
flume. Near Alma, Wis. 

erosion and absorbs much of the rainfall. Nature can control gullies, 
but the natural process of xeclaiming them after they are formed is 
very slow. 

If eroded and badly gullied land is abandoned a volunteer growth 
of some sort usually springs up. The kind of growth depends upon 
the locality. Wild native grasses, weeds, shrubs, and trees are 
the most thrifty and the best for rapid and permanent control of 
gullies. In some sections pine trees spring up spontaneously over 
eroded areas and in conjunction with weeds and grasses form a 
good natural control. Wild honeysuckle grows and spreads rapidly 
on poor soil and is very effective in controlling erosion, but because 
of its tendency to spread some farmers prefer other plants. Large 
gullies with steep, caving banks are the most difficult to control by 
* 87646°— 32 2 



natural means. They generally continue to eiJarge for many years 
after the land has been abandoned for farming. Large trees figure 
prominently in the control of such gullies. Plants which supply 
both nitrogen and humus to the soil are best for natural control,, 
for they will give to the land reclaimed for farming essential ele- 
ments of fertility. Sweetclover and black locust trees furnish 
nitrogen to the soil, and have large branching root systems which 
are effective in the control and reclamation of gullies. 

In Pendleton County, Ky., large eroded areas of abandoned 
lands have been reclaimed by the volunteer growth of sweetclover. 
When sweetclover made its first appearance in the county it was 
regarded as a weed of the worst kind because of its big root system 
and prolific growth. Many farmers who formerly devoted much 
time to ridding their places of this plant now gather the seed and 
sow it on their worn-out gullied lands, having noted the large crops 
grown on abandoned lands reclaimed by the volunteer growth of 
sweetclover. 4 


Plowing-in and seeding is a simple though sometimes rather ex- 
pensive method of reclaiming gullies. It is applicable to both large 
and small gullies with small drainage areas and has been successful 
in all sections of the United States. 

Small gullies • (1 to 3 feet deep) with no well-defined drainage 
areas should be entirely filled. They can be first partly filled with 
manure, straw, corn stalks, or small brush, which should be covered 
with a foot or more of dirt by plowing and scraping in the edges 
of the gullies. If it is not desired to cultivate the hillside, seeding 
the land and keeping it in meadow or pasture, or devoting it to 
the growth of timber will largely prevent erosion. If the land is 
to be cultivated it should first be terraced. 

For shallow gullies, or deep gullies with gently sloping banks, 
the plowing is begun in the bottom or as near the bottom as possi- 
ble. The dirt is thrown toward the center of the gully from both 
sides. The plowing is done in the same way as in breaking land 
and is continued a few furrows beyond each edge of the gully. To 
push the dirt toward the center of the gully, an ordinary road drag 
or steel ditcher can be used to advantage after each furrow. If 
the upper part of the side slope is steep it is cut down and rounded 
off with a mattock. In case sufficient dirt has not been moved into 
the gully after the first plowing, the plowing may be repeated 
until the desired filling is obtained. If the side slopes are too 
steep for a team to walk on, a chain hitch to the plow will permit 
plowing on the slope when the team is on the edge of the gully. 

In plowing-in a deep gully with nearly vertical banks the team 
is made to walk as close to the edge as possible, and the upper edge 
of the bank is plowed into the gully. The second furrow cuts the 
first deeper and the third takes another slice below the second. A 
long chain is attached to the plow so that it can be operated down 
in the gully while the team walks along the upper edge. 

* For information on sweetclover see Farmers' Bulletin 1005. 

gullies; how to control and reclaim them 9 

After the first line of furrows has reached as far down as the 
plow can be operated, the process is repeated by starting at the top 
again, the object being to reduce the side slope. If the gully is not. 
too deep the side slopes can be so reduced in a short time that the 
team can walk up and down them and across the gully. The team 
and a scraper can then be used w reduce the side slopes still more 
and to distribute part of the soil over the bottom of the gully, or the 
method described for gullies with gently sloping banks can be 

The freshly plowed earth on the sides and bottom of the gully 
affords a good seed bed. Grasses should be sowed or trees planted 
to hold the soil in place, and temporary dams of some material such 
as brush or straw should be built to catch the loose soil that might 
otherwise be washed away by heavy rains. Some of the grasses that 
can be used for this purpose are Bermuda grass, orchard grass, blue- 
grass, redtop, sweetclover, and Lespedeza. Every locality has cer- 
tain grasses best suited to it. Bermuda is probably one of the best 
grasses for southern conditions, and provides excellent pasture for 
stock. Wild honeysuckle grows luxuriantly in the South on almost 
barren soils. A more rapid growth can be obtained in gullies by 
supplying fertilizer elements in which the soil is deficient. Manure 
will provide these for most soils. Sorghum is very effective in 
controlling erosion in gullies. 

On the State agricultural experiment station farm near Holly 
Springs, Miss., some very badly gullied lands were reclaimed by the 
plowing-in and filling method. Areas of the type shown in Figure 
8 were reclaimed on this farm. The filled-in gullies were seeded to 
Lespedeza or to Bermuda grass. Most of the land was then terraced 
to keep the water from flowing down through the gullies. In some 
instances, on this farm and others, dynamite was used to advantage 
in leveling down and filling gullies. The banks were broken down 
and blown into the ditch by placing explosives in a row of holes 2 
to 4 feet from the edge of the gully, depending upon its depth, or in 
# *a row of horizontal holes in the sides and near the bottom of the 
gully. The first method is preferable for gullies with broad sloping 
banks and the second for gullies with high, steep banks. 

tiling and plowing-in gullies 

After plowing-in, further erosion in a gully is sometimes pre- 
vented by the use of tile. Large tile, the size depending upon the 
area drained by the gully, is laid down the middle. The water may 
be conducted into the tile from a catch basin at the upper end of the 
gully or by building a dam across it and extending the tile through 
the dam. 

planting trees to control gullying 

In many localities gullying has been effectively checked by plant- 
ing trees. This method is particularly adapted to land that is very 
steep or that has been gullied so badly that the cost of reclaiming it 
for pasture or cultivation would be prohibitive. In addition to 
building up the land the wood lot thus formed may be made a paying 



investment to the farmer, furnishing firewood and small timbers. 
In the South the black locust is an excellent tree for this use. North 
of the Kansas-Nebraska line it is very commonly attacked and de- 
stroyed by the locust borer. The black locust is a legume and builds 
up soil by contributing nitrogen. It has a large interlacing root 
system which holds the soil particles together and prevents washing. 
It grows to the size of a good fence post in about 10 years and is 
especially adapted for posts on account of the durability of its wood. 
Other trees 5 that are used in different sections for planting on eroded 
areas are pine, catalpa, yellow poplar (tulip), walnut, and red and 
black oak. 

In planting trees on gullied and eroded areas the best results are 

Ficure 11. — Gully formerly deep with steep banks reclaimed by locust trees and brush 
dams. Near Martin, Tenn. 

. obtained by plowing the entire gully and thoroughly disking or har- 
rowing the ground. The trees should be set out in rows 5 to 6 feet 
apart in deeply plowed furrows. The rows on the sides of the gully 
should be laid out approximately on the level, as the trees should be 
cultivated the first year by throwing the dirt from each side toward 
them. Less washing occurs where the rows closely follow the con- 
tour of the ground. It is very important that the soil bed be prop- 
erly prepared, as this will promote a rapid growth of the trees, and 
they are less likely to die at the start. 

The best results are obtained where some kind of dam is built 
across the gully to catch and hold any soil that otherwise would be 
carried away in the drainage water. Brush dams are commonly 
used for this purpose; before they rot out the tree root systems will 
have extended so as to prevent serious washing. (Fig. 11.) It is 

8 For a list of trees adapted for use in the various sections of the United States the 
reader is referred to Farmers* Bulletin 1177, Improvement of Farm Woods. 



also a good plan to sow grass seed between the trees after setting 
them out. 

This grass should not be pastured, at least not closely, because close 
pasturing greatly retards reclamation. Where a thicket of locust 
is desired and the trees are not needed for posts, they are sometimes 
cut down after the first year ; this causes sprouts to spring up between 
the tree rows and provides a dense growth which is effective in 
checking erosion. 

Willows have often proved effective in checking erosion in a gully. 
They should be set out at intervals in rows across it. They require 
an abundance of water for rapid growth. 6 


The common method of controlling or filling in and reclaiming 
gullies consists of building soil-saving dams across them. 

Temporary dams are built of stakes, brush, straw, logs, loose rock, 
or woven wire; permanent dams are built of earth, masonry, or con- 
crete. Their cost is often very small if materials available on the 
farm are used. Stones are a nuisance in a field, but are excellent 
material for dams. If no stones are available, timber and brush may 
be plentiful and log and brush dams may be built at small expense. 
Where none of these materials is available straw may be plentiful 
and can be used for low dams, the straw being held in place by stakes. 
Woven-wire fencing costs little and is excellent material for low 

Most temporary dams are porous; that is, when first built they 
permit the water and part of the silt to pass through them. They 
are gradually built up as the spaces are filled with trash and soil 
brought down by the water and are never subjected to the heavy 
pressure exerted on a water-tight dam by the water ponded above. 

Most permanent dams are water-tight, and in order to pass from 
the upper to the lower side of the dam the water must either flow 
over it, be diverted around it, or carried through it by a conduit. If 
the water is to flow over the dam, a spillway of nonerosible material 
is provided, generally at the middle of the dam, and should be wide 
and deep enough to remove the greatest flow of water expected. If 
the water is to be diverted around the ends of the dam, it is generally 
made to flow over firm, sodded ground. Sometimes a shallow chan- 
nel is dug to carry the water around the end of the dam and empty 
it into the gully at a considerable distance below. If the water is 
to pass through the dam, it is carried in a pipe. 

The inlet consists of a vertical pipe connected to a horizontal line 
of pipe extending through the dam along the bottom of the gully. 
The top of the inlet is lower than the top of the dam and the water 
ponded above does not flow out until it reaches the top of the inlet 
pipe. The pond above the dam practically forms a sedimentation 
basin, as the silt in the water settles to the bottom and in time fills 
the gully to the top of the inlet pipe. Such a dam is sometimes 
called the drop-inlet soil-saving dam, from its vertical inlet pipe. 

6 For information on getting out and caring for trees the reader is referred to publica- 
tions of the Forest Service, U. S. Department of Agriculture. 



It is known throughout the State of Missouri as the Adams soil- ( 
saving dam, as it is said to have been originated by J. A. Adams, 
a pioneer farmer of Johnson County, Mo. Mr. Adams has five of 
these dams on his farm; all of them have successfully filled and 
reclaimed gullies. 


In some localities stacks of straw are frequently used to form 
dams across deep, wide gullies. Where the threshing is done near 
a large gully the straw can be placed directly in the gully by the 
machine. This method is very successful for large gullies with 
very small drainage areas and little fall. Where much water flows 
through a gully the straw dam is likely to be washed out or a chan- 
nel washed around the end. The chances of failure can be reduced 
by building the dam high at the sides and low in the middle, so 
that if all the water does not seep through the straw it will flow over 
the top of the dam at the middle. 

The first straw dam should be built near the mouth of the gully 
so as to catch all the soil that is being carried away by the water. 
At the same time provision should be made to stop waterfall erosion 
at the head of the gully. After as much soil has been filled in above 
the first dam as it is thought can be held by the sod seeded there 
when the straw rots out, another straw dam should be built a short 
distance farther up the gulry, and then another until the gully is 
filled in as desired. This is a simple and easv method of reclaiming 
certain types of gullies, if a large quantity 01 straw is available. 

Further washing of small shallow gullies is sometimes prevented 
by filling them with loose straw during the fall and winter. The 
water percolates through the straw, the silt being retained. In the 
following spring the partly rotted straw is generally covered by 
plowing-in the gullies, thus adding to the fertility, and increasing 
the humus content and the absorptive capacity of the soil. On steep 
slopes or where the gullies carry much water, this method is not 
a success, since the straw is usually carried to the foot of the slope 
by the force of the water. 


Sod dams are often successfully employed to check erosion in 
small gullies draining one-quarter acre or less on moderate slopes. 
To get sod well started it is necessary to place it above a small dam 
of brush, rock, or other inexpensive material. Perhaps the best way 
is to place the sod in loosely woven grain sacks, tie these up and build 
them into small dams in the gully. Usually the filled sacks are 
placed end-to-end across the gully. Each dam should be lower in 
the middle than at the sides of the gully so as to permit the water 
to flow over without washing around the ends. Sufficient soil should 
be placed between and around the sacks — particularly on the upper 
side — to prevent water percolating through the dam. Usually a 
good sod growth has developed before the sacks are rotted out. 
Native grasses which are hardiest in the locality can be used for this 

gullies; how to control and reclaim them 



A cheap method of filling-in and reclaiming gullies of moderate 
slopes and small drainage areas consists in driving several rows of 
stakes across the gully in checkerboard fashion. The stakes should 
be 3 to 7 feet long with a diameter of 2 to 4 inches at the upper 
end. The rows should be from 6 inches to 2 feet apart, and the stakes 
the same distance apart in the rows. The stakes should be driven 
into the ground until the tops extend 8 to 20 inches above the surface ; 
the larger and longer the stakes the greater may be the intervals. 
The rows of stakes should extend across the gully and up the sides 
as high as water ever reaches, and the tops of the stakes on the sides 
of the gully should 
be at least 1 foot 
higher than the 
tops of the stakes in 
the middle. The 
stakes may be made 
of any available 
hard wood. When 
stones are available 
the dam can be 
made more substan- 
tial by filling in the 
spaces between the 
stakes with them, as 
shown in the three 
lower dams in Fig- 
ure 12. Where 
stone is not avail- 
able the ability of 
the stakes to check 
and hold silt can be 
increased by filling 
in straw between 
them. A series of 
such dams should 
be built along the entire length of the gully, the distance between 
them being such that each dam will cause a deposit of silt extending 
to the next above. As soon as the filling in above the first series of 
dams is completed other dams should be built between the first ones 
and the filling-in process continued by additional dams until the 
gully is filled as desired. 


In localities where timber and brush are abundant excellent results 
have been obtained by the use of brush dams. The methods of 
building these dams differ somewhat in different sections of the 
country. In hillside gullies where the flow of water is small the 
dams are commonly built of loose brush, sometimes weighted down 
with logs or rocks. Where the flow is sufficient to overtop the dam 
the brush can be held down by crosspieces or wire and stakes, or 
the dams are sometimes built by weaving brush into a row of stakes 

Figure 12. — A series of stake dams in a gully. The spaces 
between the stakes in the three lower dams are filled with 



across the gully. Successful results can not be obtained by simply 
dumping brush into the gully. 

In reforesting gullied lands in Tennessee, the State forester has 
used loose-brush dams extensively. The dams are built to catch and 
hold soil in the gullies until the planted trees are able to hold the 
soil against erosion. 

In building these dams, trees are first dragged to the site of the 
gullies, and the branches are cut off. Several layers of branches 
with the tops pointing downstream are first laid for the foundation 
of the dam. This is to prevent slipping, as the greater part of the 
dam is built with the branches extending crosswise of the gully. 
The dam is built up by laying the branches close together across the 
gully, but occasionally a layer of branches is placed with the tops 
pointing upstream and extending beyond the face. When these 
branches become covered with silt they tend to hold the dam more 
securely in place and tie the brush together. After the dam is built 
about 3 feet high, logs furnished by the trunks of the trees are laid 

across on top of the brush length- 
wise of the dam to hold it down. 
The dams are built lower in the mid- 
dle so that the water will flow at that 
point and prevent washing around 
the ends. Dams built in this man- 
ner can be used only where the 
drainage area of the gully is very 
small ; where there is a large flow of 
water they are likely to be floated 
away or washed out. (Fig. 11. ) 

Where the water in a gully is suf- 
ficient to overtop a brush dam it is 
necessary to anchor the dam more 
securely. M. H. Hoffman and A. W. 
Turner, formerly of the Iowa State 
College extension department, who 
have had wide experience in building dams of this type, recommend 
the following method for building dams that are at times overflowed. 
The bottom and sides of the gully for a distance of 4 to 10 feet are 
covered with a layer of straw that will be from 4 to 6 inches deep 
after being pressed down by the weight of the dam. The brush, 
with the butts pointing upstream, is laid close together on the straw 
and thoroughly tramped down, the fine brush being placed at the 
bottom and the coarser on top. The packed brush is held in place 
by crosspieces nailed to fence posts set in the line of the dam across 
the gully as shown in Figure 13. It is important that the fence 
posts be set well in the ground, usually not less than 4 feet deep. 
The figure shows the middle of the dam lower than the sides so that 
the water will not have a tendency to wash around the ends. 

Another method of anchoring such a brush dam is to drive several 
rows of stakes across the gully, the rows 2 feet apart and the stakes 
1 foot apart in the row. The gully is partly filled with brush before 
the stakes are set in place and lightly driven in. Sufficient brush to 

Figure 13. — Straw and brush dam held 
in place by crosspieces and posts 7 

7 From Bulletin 77 of the Iowa State College agricultural extension department. 

gullies; how to control and keolaim them 15 

complete the dam is then placed and, heavy wire is stretched along 
the rows of stakes and fastened to them. Finally the stakes are 
driven in until the wire holds the brush firmly in place, the dam 
being made lower at the middle than at the sides of the gully. 

The poles from which the brush was trimmed can be used in 
anchoring a brush dam, especially where rock is encountered in the 
bottom of the gully and stakes can not be driven. The poles are 
set diagonally into the lower part of the bank on both sides of the 
gully, about 3 or 4 feet apart, and bent over to the top of the oppo- 
site bank, (Fig. 14.) The larger ends are set into the ground at 
such an angle that the poles from opposite sides cross 2 or 3 feet 

Figure 14. — Brush dam anchored with poles under construction in tbe background, 
and two completed dams in the foreground. Near Guthrie, Okla. 

above the bottom of the gully. The brush is then laid between the 
lower parts of the poles and under the upper parts, so that when the 
tops of the poles are bent down it will be held compactly and 
securely and will be lowest in the middle of the gully. The dam 
usually extends 10 or 15 feet along the gully. InFigure 15 is a view 
of a gully reclaimed with brush dams. The filling above the dams 
was caused by only a few rains. 

The average cost of building brush dams 10 to 15 feet long, 2 feet 
high, and 4 to 6 feet wide, on a soil-erosion experiment farm near 
Guthrie, Okla., was about $1 for loose-brush dams, and $4 for brush 
dams anchored with stakes and wire or cross poles. A number of 
brush dams anchored with poles about 10 feet long, 1 foot high, and 
4 feet wide, cost about $1.50 each and several averaging 23 feet long, 

87646°-r32 3 


3 feet high, and 8 feet wide, cost about $12 each. These costs are 
based on the actual labor and material required to build the dams 
and do not include the cost of cutting and hauling the brush to the 
site of dam, this cost having been charged to the clearing of the land. 

In Europe woven-willow dams, sometimes called wattled dams, 
are rather common and have proved very satisfactory. Live willow 
stakes about 3 or A inches in diameter and 3 to 5 feet long are driven 
in a row across the gully about 6 inches apart with their tops about 
iy 2 feet above the ground. The row of stakes should extend as far 
up the sides of the gully as the highest water, and the middle of the 

Figure 15. — Reclamation of gully by brush dams. The filling above the dams 
occurred during only a few rains. Near Guthrie, Okla, 

dam should be lower than the sides. The stakes are held together 
by weaving willow branches between them from top to bottom. 
As shown in Figure 16, a brush apron is made below the dam to 

{)revent underwashing. This apron is built of branches 6 to 8 feet 
ong laid lengthwise of the gully in a trench about 6 inches deep. 
The butts of the branches are laid upstream and are partly buried in 
the bottom of the gully, and the downstream ends are held down by 
a pole laid across them and spiked to a second row of stakes about 3 
feet from the first row. The wattled dam is used to some extent in 
this country. Pine branches are sometimes used in place of willows. 

Another form of brush dam, very common in Europe, is the fascine 
dam. It is made of bundles of brushwood 8 inches to 2 feet in 
diameter and from 7 to 14 feet long. The bundles are tied together 
in several places with wire. They are laid with their length across 

gullies; how to control and reclaim them 


the gully and rest against a row of posts set about 3 feet apart. The 
posts are of the size of ordinary fence posts and are driven or set into 
the ground at least 4 feet. The bundles are held in place by driving 
stakes through their centers 1 to 2 feet apart. Trenches are dug into 
the sides of the gully, and the ends of the bundles are extended into 
them to prevent washing around the ends of the dam. The dam is 
made lower in the middle, and an apron 
of brush to prevent undermining is built 
below the dam in the manner described 
for the woven-bush dam. The middle of 
the dam is iy 2 to 2^ feet high. 

The brush dam is cheap and easy to 
build and when carefully and properly 
constructed is effective in filling gullies. 
For this reason it is popular among 
farmers and is employed to some extent in 
every section of the United States where 
timber is available. It is best suited for 
gullies with small drainage areas. 

When a farmer has a large quantity of 
brush to dispose of, a very common prac- 
tice is to fill the whole length of large, 
deep gullies with brush which is thor- 
oughly tramped down and sometimes 
weighted with rock or other heavy ma- 
terial. When the whole gully is filled it 
is practically impossible for the force of 
the water to move the brush and the silt 
is caught and held by the brush as the 
water flows through. Sometimes sections 
25 to 50 feet in length are filled solid with 
brush at intervals along the gully. The 
huge dams of brush eventually cause the 
filling of the gully between. Another 
practice is to shingle the bottom of the 
gully with brush (as the roof of a house 
is shingled) , commencing at its lower end 
and laying the brush with the tops point- 
ing upstream. If the water is likely to 
dislodge the brush it can be held in place 
by crosspieces fastened to stakes at inter- 
vals along the gully or it can be weighted down with rock. Leaves 
scattered over the brush assist the catching of silt. After the first 
layer of brush is covered with silt, other layers can be placed on top 
until the gully is filled. This practice is especially applicable in 
filling the lower end of a gully where the fall is not great. 


Like the brush dam, the woven-wire darii is found in every section 
of the United States. It consists essentially of a low fence across a 
gully. The posts must be set close together and anchored solidly 
upstream if the force of the water is great. 

Figure 16. — A woven-willow brush 
dam. A, Front view. B, Top 
view. C, Side view 



The common method of building these dams consists in setting a 
row of ordinary fence posts across the gully about 4 feet apart. The 
posts should be set at least 4 feet deep and should be anchored by 
wire to anchor posts driven 8 or 10 feet above the line of the dam. 
The deposit of soil caught by the dam later covers these anchor posts 
and greatly increases their holding power. The end posts should 
be set in a trench dug into the sides of the gully. The best re- 
sults are obtained when a trench is dug along the upper side of 
the posts so that the woven wire may be fastened 6 inches or a 
foot below the surface. The wire should be at least 30 to 36 inches 
wide and should be set into the ground so that about 2 feet extend 
above the surface. The wire is fastened to the upper sides of the 
posts, and the trench in the sides and across the gully is filled up 
and carefully tamped. When there is not enough trash in the water 

Figure 17, 

-Newly constructed woven- wire-fencing dam built to control erosion at bead 
of gully. Near Alma, Wis. 

to close the large meshes in the wire and catch the soil particles, 
a little straw, leaves, or fine brush can be placed against the upper 
side of the wire to get a fill started. Angle-iron posts are sometimes 
used instead of wooden posts. (Fig. 17.) 

A dam of this type is especially suitable for use in gullies with 
moderate slopes and small drainage areas. It is also very effective 
in checking head erosion at the upper end of a gully. 


l : Poles from which the brush has been trimmed for brush dams 
*ean be used in the construction of pole dams. The poles are laid 
across the gully in layers, the bottom layer being 2 to 4 feet wide 
and the top layer one pole wide. The lower poles are laid in a 
trench one pole deep and extend into the sides of the gully about 2 
feet. The poles should be fastened together with spikes and wire. 
An apron of poles, extending along the gully for a distance of 3 or 4 
feet below the dam, is built to prevent the overflowing water from 
eroding the bottom of the gully and undermining the dam. A notch, 

gullies; HOW TO CONTROL and EECLAIM them 


2 to 4 feet wide and 1 to 2 feet deep depending upon the size of the 
gully, should be left in the center of the dam to permit the water to 
pass over without eroding the sides. The poles should be laid in 
grass or straw and earth should be placed and tamped on the upper 
side of the dam to prevent water from flowing through or around 
the ends. Figure 18 shows three pole dams in a gully. Most of the 
silt above these dams was caught during one heavy rain. Actual 
records show that a pole dam about iy% feet high at notch and 8 feet 
wide cost about $4 and 3 feet high at notch and 12 feet wide at top 
can be built for about $10. 

Figure 18. — Three pole dams in a gully. Most of the silt above the dams was 
caught during one heavy rain. Near Guthrie, Okla. 


Where timber is abundant log dams are very commonly built to 
check gully erosion. The simplest dam for small narrow gullies is 
made by placing a large log in a shallow trench across the gully. 
The trench is cut into the sides of the gully so that the ends of the 
log extend into both sides. Other smaller timbers about 6 or 8 feet 
long are laid close together lengthwise of the gully, with the down- 
stream ends resting on the log and the other ends on the bottom 
of the gully above the log. The timbers are spiked to the log. Old 
railroad ties are sometimes used for the timbers. Dams built in 
this manner have been very successful in filling gullies that drain 
small areas. 

Another simple type of log dam is built as follows : Posts are set 
in a row across the gully 4 feet apart, about 4 feet deep, their tops 



I 1 1 i I I 

extending 3 or 4 feet above the bottom of the gully. A trench is 
then dug on the upstream side of the posts extending about 2 feet 
into the sides of the gully. A log is laid in this trench, which is 
just about deep enough to bury it, and other logs are laid on top of 
the first, until the top log is as high as the top of the posts. The 
logs are held in place by piling dirt against them, by driving small 
stakes on the upper side at the ends of the logs, or by spiking them 
to the posts. A section of the top log between the two posts nearest 

the center of the dam is cut out to 
provide a way for the water to flow 
over the dam and prevent washing 
around the ends. (Fig. 19.) The 
bottom of the gully should be paved 
with stone for about 4 feet below the 
dam, or may be protected from 
erosion by laying small logs to- 
gether as a floor, holding them in 
place by stakes driven along the 
lower side. Where rock is plenti- 
ful loose rock is placed below the 
dam to prevent erosion by the fall- 
ing water. Unless one of the above 
methods is employed the dam is 
likely to be undermined. 

Where it is difficult to drive or 
set posts in a gully the logs may be 
held in place by other logs laid 
obliquely across them with the ends 
notched to fit into corresponding 
notches between the logs of the dam. 
The free ends of the oblique logs 
are covered with dirt, and their hold 
becomes stronger as the fill above 
the dam grows deeper. (Fig. 20.) 

Where both timber and stone are 
plentiful crib dams are sometimes 
built. The crib dam consists of a 
framework or box of logs across 
the gully, filled with rock fragments 
or stones. The ends extend into 
the sides of the gully, and the dam 
is built in a trench dug across the 
^ • •-■ i /• i ji * bottom. Undermining is prevented 

Figure 19. — Dam built of logs and posts , . « , to f , , 

with spillway at center and stone pave- by a pavement 01 Stone belOW the 

ment below the dam : A, Front view ; ji 

B, top view ; C, side view 


Posts cut from green willow trees are used very effectively to fill 
gullies. They are set 2 or 3 feet apart in rows across the gully, 
sometimes several rows of them close together. Where there is 

gullies; how to coxtkol and reclaim them 21 

plenty of water the willow posts take root and grow ? forming a hedge. 
Trash and silt are caught above this hedge, causing a fill of soil. 
Straw or loose, small brush 
may be thrown above the wil- 
lows to assist in getting a fill 

When quicker results are 
desired, a row of willow 
posts, 3 or 4 feet apart, is set 
across the gully, and railroad 
ties or logs are laid one on 
top of another above the 
posts in a manner similar to 
that described for log dams. 
Willow dams are usually 
built at the lower ends of 
gullies near main water 
courses or where the soil is 
naturally moist throughout 
the year, for the rapid and thrifty growth of willows depends upon 
abundant water. 


Rock is a very good material for building low soil-saving dams. 
Its use is particularly advisable on farms where rock is plentiful and 
often a nuisance in the fields. Loose-rock dams should not be more 
than 2 to 3 feet high and should be built only in gullies of moderate 


FJQIThl — Log dam held by notched logs extend- 
ing obliquely into the sides of the gully 

Figure 21. — Loose-roek dam in highway ditch. Note sediment caught above dam 

slope and small drainage areas. The dam should be 4 or 5 feet wide 
at the base and about 2 feet wide on top. The rock should be so 



arranged that the small pieces fit in among the large. Only large 
pieces should be used on the top of the dam, as a current of water has 
often sufficient force to move even large stones. The dam should be 
built well into the banks of the gully and should be lowest in the 
middle. A trench about 6 inches deep should be dug across the gully, 
in which the foundation of the dam, consisting of the largest rock, 
should be laid. The gully below the dam for about 5 feet should be 
covered with loose rock to prevent erosion and the undermining of 
the dam.* Figure 21 is a view above a loose-rock dam in a highway 


Masonry dams instead of loose-rock clams are usually built where 
a greater height than 3 feet is desired, where the flow in the gully is 
large, or where rock is not plentiful and its economical use is neces- 

Figure 22. — Masonry dam built across a gully draining over 1,000 acres. This dam 
extends well into the banks and is lower in the middle than at the ends. Near 
Kansas City, Mo. 

sary. The construction is similar to that of a masonry wall, and the 
sides should have a batter of 1 in 5 or 1 in 10. The thickness at 
the bottom should be about one-half the height, and the base should 
be 1 to 2 feet below the bottom of the gully for dams 3 to 6 feet high. 
Dams of this kind higher than 6 feet are not recommended unless an 
excellent foundation is obtained, special precautions taken against 
undermining, and the walls are extended far enough into the banks 
of the gully to prevent cutting around the ends. The services of an 
engineer would be required to build a high masonry dam, and hardly 
any two gullies would require the same design. 

Water may be made to flow over the central portion of dams 3 or 
4 feet high by gradually increasing the height of the dam from some 
point near the middle toward the ends, as shown in Figure 22. 
Where the ends of the dam are extended well into the banks it is not 
necessary for the base at the ends to be as low as the base across the 
gully. Loose rocks should be placed below the dam to prevent wash- 
ing and undermining. 

gullies; how to control and reclaim them 


A dam higher than 4 feet should have a notched spillway in the 
middle to confine the overflow water to the middle portion of the 
dam, and a carefully paved floor should be placed below the spill- 
way to prevent undermining by the falling water. Masonry dams 
more than 3 or 4 feet high are not much used in the reclamation of 
gullies, owing to the high cost and the difficulty of making them 


Failures of concrete dams are usually the result of poor design 
and faulty construction. Lack of knowledge of the erosive action 
of moving water and of the pressure exerted by standing water, and 
the desire to keep costs low are responsible for many failures. 

A spillway should be provided for passing water over the dam, 

FiGunE 20. — Concrete dam across large gully with ends of dam extending to top of the 
banks of the gully. This dam was built to fill the gully and prevent enlargement 
where the highway bridge crosses. A fill of 8 feet haa occurred above the dam. 
Near Mason City, 111. 

usually at the middle, to prevent injury to the structure. If the top 
of the dam is level, with no spillway, water will flow over the entire 
dam and will invariably cut away the earth around one or both ends, 
forming a channel which will allow the accumulated silt to escape. 
The ends of the dam should extend to the top of the gully, or at 
least a*s high as water is expected to rise, to prevent water from 
coming in contact with the sides of the gully. (Fig. 23.) The ends 
should extend into the sides of the gully far enough to prevent water 
from seeping around them and causing a washout. 

In Figure 24, are shown the plan, elevation, and side view of a 
reinforced concrete dam recommended by the agricultural extension 
department of the Iowa State College. It is claimed for this dam 
that " it has a firm foundation, extends well into the banks, has an 
adequate spill platform, * * * and has a means of relieving the 
water pressure/' This design was proposed by the extension depart- 
ment after making comprehensive investigations of concrete dam 
failures throughout the State of Iowa, and it especially guards 
against the common causes of failure. 



In Figure 25 is shown a series of low reinforced concrete dams 
employed principally to check erosion. These dams are especially 
suitable for use in small gullies and roadside ditches with small 
watershed areas. The wing walls are extended well into the sides of 
the gully or ditch, and a concrete apron is provided below each dam 
to prevent undermining. 

Concrete dams are built of either plain or reinforced concrete. 
Dams not exceeding 3 or 4 feet in height are usually built of plain 
concrete, and higher ones of reinforced concrete. Failures often re- 
sult from the use of poorly made concrete. A good concrete mixture 
is 1 part cement, 3 parts sand, and 6 parts stone or broken rock. A 
competent engineer should be engaged to design and construct a 

Figure 24. — Plan, section, and downstream view of a concrete dam especially designed 
to guard against the common causes of failure 8 

reinforced concrete dam. No one design is applicable to all con- 


Earth dams of two different types are used. In one type the sur- 
plus water is carried around or over the dam by spillways, and in 
the other it is carried through the dam by a pipe. In many in- 
stallations the principles of both types are employed. Earth soil- 
saving dams are generally employed to fill very large gullies, though 
they are rapidy growing in favor for use in small gullies, particu- 
larly where no other cheap material is available for the construction 
of low dams. 

If a spillway is used to carry the water around or over the dam, 
a pond is formed above the dam, and if the capacity of the pond is 
not sufficient to hold the greatest run-off from the drainage area the 
surplus water is conducted through a channel around one end of the 
dam, or over the dam in a sheet-metal or plank flume. Because of the 

8 From Bulletin 80 of the Iowa State College agricultural extension department. 


chances of injury to the dam, the latter method is not recommended, 
however, unless it is impossible to carry the water around one end 
of the dam over firm ground. 

In the other type of earth soil-saving dam vitrified sewer pipe, cor- 
rugated metal pipe, or a rectangular box built of concrete or creo- 
soted lumber is generally used to carry the water through the dam. 
A cross-sectional view of a dam of this type is shown in Figure 26. 
Water from heavy rain fills the basin above the dam, the silt settles 
to the bottom of the basin, and the water flows through the vertical 
inlet pipe and the pipe through the dam into the gully below. When 
silt fills the basin to the top of the inlet pipe another section of pipe 

Figure 25. — Series of reinforced concrete dams used to check erosion in a highway 


may be added and the filling continued. The top of the inlet pipe 
should be at least 3 feet below the top of the dam, and where^ con- 
ditions permit, the top of the dam should be at least 1 foot higher 
than the firm ground on the sides of the gully after the dam has 
settled, so that if an unusual rain occurs — heavier than the pipe can 
handle — the water will flow over the firm ground, not over the top 
of the dam. The vertical inlet pipe should preferably be set 10 feet 
or more from the inside toe of the dam, because at that distance it 
is not likely to become clogged with floating trash that usually ac- 
cumulates near the dam. Also there is less danger of water eddying 
around the inlet pipe and causing a break in the dam. The usual 
practice is to set the inlet pipe close to the dam, because less pipe is 
required. This practice is no doubt responsible for a great many 

Another precaution against possible clogging of the inlet pipe is 
to wrap ordinary woven fence wire round four posts set around the 



pipe, with the bottom of the wire a little lower than the top of the 
inlet pipe. This permits the water to pass, but keeps out the float- 
ing trash. Where it is desired to keep the gully drained above the 
dam and thus prevent the formation of a pond, the vertical inlet pipe 
is joined to the horizontal pipe by a tee connection, and to one end 
of the tee is connected a drain pipe that extends up the gully. 

In many instances farmers desire to make the dam serve the 
double purpose of filling the gully and furnishing a watering place 
for stock. In such cases an elbow connection is used in place of the 
tee, or the end of the tee is plugged with a vitrified clay stopper 
cemented in the pipe. A foundation of stone or concrete should be 
provided for the tee or elbow of the inlet pipe. The flow of the 

Figure 26. — Drop-inlet and earth soil-saving dam' 

water into the vertical inlet pipe can be facilitated by placing a 
hopper pipe on top of the vertical inlet. (Fig. 27.) 

The pipe through the dam and the joints of the vertical inlet pipe, 
with the exception of the top joint, should be cemented. Great care 
should be used in laying the pipe through the dam. A trench with 
enough fall to prevent water from standing in the pipe should be 
dug m the bottom of the gully, and holes should be dug under the 
bell of each pipe so that the barrel rests on firm ground. After 
the joints are cemented and dried, clay soil should be placed around 
the pipe and thoroughly tamped, tamping should be continued 
over the pipe until it is covered with 2 or 3 feet of soil. Unless the 
soil forms a close bond with the pipe, water is likely to seep along the 
pipe and often washes a hole through the dam. (Fig. 28.) Seep- 
age along the pipe can be prevented by building a concrete cut-off 
wall at the middle of the dam as shown in Figure 26. If a firm 
and even foundation for the pipe is not obtained, a little unequal 
settlement due to the weight of the earth above may cause leakage 
through breaks in the joints of the pipe. 



Protection against erosion should be provided where the water dis- 
charges from the outlet pipe into the gully below. More important 
than preventing erosion of the gully below the dam is the prevention 
of undermining and eating-back through the dam along the pipe. 
In Figure 26 is shown a channel built of concrete to stop erosion 
at the outlet of the tile. This channel is usually made 6 to 10 feet 
long, depending upon the vertical drop of the water. The greater 
the vertical drop the greater will be the velocity and eroding power 
of the water. Where it is desired to keep the water out of the gully 
below the dam the tile can be extended beneath the ground down 
through the gully to a suitable outlet. 

Under Outlets for Soil-Saving Dams (p. 30) the size of out- 

Figure 27. — Vertical inlet pipe newly constructed, showing hopper pipe on top and end 
of T plugged with vitrified clay stopper cemented in the pipe. Near Marshall, Mo. 

let pipe required is thoroughly discussed, and Table 1 gives the 
sizes of pipe to use for soil-saving dams. If the pipe is too 
small, overtopping and washing out of the dam generally occurs. 

The foundation of the dam should be prepared by clearing away 
all weeds, growths, and debris and plowing the site to reduce the 
possibility of seepage along the bottom of the dam. Another pre- 
caution against seepage often advisable, especially where the dam is 
10 feet or* more in height, is to dig a trench the length of the dam 
6 to 10 feet wide and iy 2 feet deep. The sides of the trench should 
be made vertical so as to break the seam between the natural ground 
and the dam, and the bottom of the trench should be plowed. The 
dam should be built in layers about 1 foot in depth. It is usually 
built with teams and scrapers, the material being tamped and com- 
pacted by the horses' feet and the scrapers. The best results are 



obtained when the loose earth is sprinkled with water, which facili- 
tates the compacting of the embankment and makes it more imper- 
vious. The top of the dam should be not less than 4 feet wide, the 
side slopes on both faces of the dam not less than 1% horizontal to 
1 vertical. The top of the dam should be not less than 3 feet above 
the bottom of the spillway or top of the vertical inlet pipe. In Fig- 
ure 26 is shown a section recommended for an earth soil-saving dam. 

The best material for building an earth dam consists of 1 part clay 
to 2 or 3 parts gritty earth. Where water is not available for damp- 
ening the material it is best 
to construct the dam during 
the rainy season so that the 
earth in the borrow pit may be 
kept damp by rains. Material 
for building dams should pref- 
erably be taken from above the 
dam, 20 to 25 feet above the up- 
stream toe. An allowance of 
about 10 per cent should be 
made for the settling of the 
material in the earth embank- 
ment. Where the top of the 
earth dam is used as a roadway 
it should be at least 8 feet wide. 

The popularity of the drop- 
inlet, earth soil-saving dam is 
growing rapidly. In Saline 
County, Mo., several hundred 
have been built, one farmer 
having 14. In this county they 
are made in small gullies as 
well as large, and are placed 
one above another in the same 
gully so that the fill from one 
reaches nearly to the outlet of 
the next dam above. 


Gullies often cause much 
trouble and expense in build- 
ing and maintaining public 
highways. Bridges are required to cross them, and where the gullies 
are growing wider the length of the bridges must constantly be 
increased. A notable example is a bridge over a gully near Falls 
City, Nebr. Thirty-five years ago the gully did not touch the road ; 
since then it has crossed the road and continually widened. A trestle 
185 feet long crosses the gully, and its length has been repeatedly 
increased as the abutments for the approach spans have been under- 
mined by the caving in of the sides of the gully. The drainage area 
above this bridge is only about 70 acres; the water from this area 

Figure 28. — Results of water seeping along 
outside pipe through a dam 

gullies; how to control and keclaim them 29 

could readily be removed by a moderate-sized culvert. In this case 
further erosion could be stopped by building a road embankment 
with combined concrete drop inlet and culvert as shown in Figure 29. 

In Figure 30 is shown a close view of a concrete drop inlet, and in 
Figure 31 is shown its design, which was furnished by the county 
engineer, of Madison County, Iowa. The cover over the drop inlet 
prevents animals from falling in, but interferes with the flow to 
some extent. In place of the cover a fence might be built to keep 
animals out. 

Gullies of the waterfall type often eat their way slowly up a 
watercourse toward a highway. Generally no attempt is made to 
check the gully until it has reached the road. The usual method 
then employed to stop it from crossing the roadway is to build a 
concrete structure to prevent further erosion and the undermining 
of the roadway and culvert. Figure 2 (p. 2) shows such a struc- 

Figure 29. — Highway bridge to be replaced by an earth embankment and a combined 
culvert and concrete drop inlet. Near Winterset, Iowa 

ture built at great expense. At the time the picture was taken the 
structure was partly undermined. About a year after the work was 
completed the roadway and structure were washed out. The failure 
was due to a poor foundation and to the fact that the concrete spill- 
way did not extend far enough from the culvert. Where such struc- 
tures are required they should be properly designed and carefully 
constructed. It is invariably more satisfactory and less expensive 
to stop the gully in the farmer's field before it has reached the 

In building a road embankment to cause a fill in the gully above 
by^ the use of the drop inlet more care should be taken than in 
building an ordinary embankment not subject to water pressure from 
above. The best material should be placed and carefully tamped 
around the barrel of the culvert and on the upstream side of the 
embankment. Where there is danger of seepage, one or two concrete 
cut-off walls should be built around the barrel of the culvert. An 
installation which has given excellent results is shown in Figure 32. 




The permanence of a soil-saving dam depends primarily upon the 
adequacy of the outlet. The outlet may be a spillway that carries 
the water over or around the end of the dam, a pipe or conduit that 
carries the water through the dam, or often a combination of the 
two. The rate at which the water should be carried depends upon 
the size, shape, and topography of the watershed area, upon the 
quantity of water that can be stored by the dam, and upon the in- 
tensity and amount of heavy rains. 

In concrete or masonry structures controlling large drainage areas 
provision should be made for the water to flow over the entire length 
of the dam in case of unusually heavy rains. The ends of the dams 
should be extended as high as the banks of the gully or as high as the 
highest water expected in the 

r " ' /.* \ -5 "l / \ ; *] gully. 

In the case of earth soil-sav- 
ing dams a spillway should 
always be provided around one 
or both ends of the dam, where 
possible, by building the top of 
the dam higher than the nat- 
ural firm ground on either side 
of the gully. The greater this 
height the greater will be the 
factor of safety against the 
dam being overtopped and 
washed out. Spillways built 
of hard material over the tops 
of earth dams are not recom- 
mended, because of the diffi- 
culty of maintaining them and 
the danger of undermining 
the dam. 

It is important that the pipe 
through a drop-inlet soil-sav- 
ing dam be made large enough 
to remove heavy rainfalls, rap- 
idly enough to prevent overtopping. In Table 1 are given the sizes 
of pipe or conduit adapted -to watersheds with length equal to about 
twice the width. 

In columns 2 and 3 are given the cross-sectional area of a pipe 
or conduit required for a soil-having dam with no spillway; where 
the storage above the dam is very small, as in a narrow valley with 
a steep slope; and where the drop from the top of the inlet pipe to 
the center of the outlet end of the pipe through the dam is 4 feet 
and 8 feet. 

In columns 4 and 5« are given cross-sectional areas for conditions 
similar to those given for columns 2 and 3, except that considerable 
water is stored above the dam. Such storage considerably reduces 
the size of pipe required for small watersheds but changes it very 
little for watersheds 100 acres or more in extant. The area of con- 
duit required can be increased or decreased by increasing or decreas- 
ing the storage area. 

Figure 30. — Drop inlet and box culvert. Plan 
shown in Figure 31. The old wooden bridge 
is to be replaced by an earth fill 

GULTjIESJ HOW TO CO-ESTTEOI, and ueclaim them 


In columns 6 and 7 are given cross-sectional areas required where 
the conditions are the same as for columns 4 and 5 except that pro- 
vision is made to carry part of the flow around the dam over a spill- 


Figure 31— Reinforced concrete drop inlet for box culvert * shown in Figure 30 

way having a capacity equal to one-half the capacities of pipes or 
conduits with areas as given in columns 2 and 3. 

If the water over the spillway will have a depth of V/ 2 leet, the 
cross-sectional area of the 
flow should be four to 
eight times the area of a 
drop inlet that has the 
same capacity with 4 feet 
of drop. The farther the 
water through the spill- 
way must flow to get back 
into the gully, the larger 
should be the spillway. 

Suppose it is desired to 
know the size of a pipe or 
conduit required for a 
rolling watershed of 25 
acres with length equal to 
about twice the width, 
where the surface area of 
the water stored above the 
dam would be about one- 
half acre, where no provi- 
sion would be made for a 
spillway round or over the dam, and where the vertical drop irom the 

Figure 32. — Road embankment and concrete drop 
Inlet replacing- an old bridge that was 60 feet 
long and 35 feet Msrh. Depth of fill is 12 feet. 
Near Falls City, Nebr. 

9 Designed by E. B. Illatt, of Wlntersot, Iowa. 



Table 1. — Cross-sectional areas of pipe or conduit for drop-inlet, soil-saving 
dams for rolling watersheds with length equal to about twice the width 


With no spillway around or over dam 

With spillway hav- 
ing capacity about 
half that of pipe in 
column 2; storage, 
H acre at level of 
top of inlet pipe 

Very little storage 
above dam 

Storage above dam, 
surface area, H acre 
at level of top of in- 
let pipe 

4-foot drop 

8-foot drop 

4-foot drop 

8-foot drop 

4-foot drop 

8-foot drop 











0. 3 

0. 2 

0. 1 

0. 05 

0. 0 


. 7 

. 5 

. 35 

. 2 

. 1 

. 0 


1. 1 

. 8 

. 6 

. 3 

. 15 

. 0 


1. 5 

1. 1 


. 5 

. 2 

. 0 


1. 9 

1. 4 

1. 1 

. 65 

. 25 

. 0 


2. 2 

1. 7 

1. 3 

. 8 


. 0 


3. 0 

2. 3 

2. 0 

1. 2 

. 4 

. 1 


3. 8 

2. 8 

2. 7 

1. 7 

. 5 

. 2 


4. 5 

3. 4 

3. 4 

2. 2 

1. 1 

. 3 


5. 1 

3. 8 


2. 6 

1. 2 

. 5 


5. 8 

4. 3 

4. 5 

3. 1 


. 7 


6. 3 

4. 8 

5. 1 

3. 5 

1. 8 

1. 0 


6. 9 

5. 2 

5. 7 

4. 0 

2. 2 

1. 2 


7. 5 

5. 6 

6. 3 

4. 4 

2. 6 

1. 5 


8. 6 

6. 5 

7. 6 

5. 4 

3. 2 

2. 2 


9. 7 


8. 6 

6. 2 


2. 5 


10. 7 

8. 0 

9. 6 

6. 9 

4. 2 

2. 9 


11. 7 

8. 8 


7. 7 

4. 8 

3. 3 


12. 6 

9. 5 

11. 6 


5. 3 

3. 7 


15. 0 

11. 2 

14. 1 

10. 4 




17. 2 

12. 9 

16. 7 

12. 4 

8. 2 

6. 0 


19. 2 

14. 4 

19. 2 

14. 4 

9. 6 

7. 2 


21. 3 

16. 0 

21. 3 

16. 0 

10. 6 



28, 8* 

21. 6 

28. 8 

21. 6 

14. 4 

10. 8 


35. 8 

26. 8 

35. 8 

26. 8 

17. 9 

13. 4 


42. 3 

31. 7 

42. 3 

31. 7 

21. 1 

15. 8 


48. 5 

36. 4 

48. 5 

36. 4 

24. 2 

18. 2 


54. 4 

40. 8 

54. 4 

40. 8 

27. 2 

20. 4 


60. 2 

45. 2 

60. 2 

45. 0 

30. 1 

22. 5 


65. 7 

49. 3 

65. 7 

49. 2 

32. 8 

24. 6 


71. 1 

53. 3 

71. 1 

53. 3 

3.5. 6 

26. 6 

For very hilly watersheds increase above cross-sectional areas 25 per cent. 

For square or fan-shaped watersheds increase above cross-sectional areas 15 per cent. 

For sizes of pipes corresponding to the above cross-sectional areas see Table 2. 

Table 2. — Cross-sectional areas of pipes of standard diameters jor use in selecting 
sizes corresponding to areas in Table 1 





of pipe 

area of pipe 

of pipe 

area of pipe 


Square feet 


Square feet 


0. 20 


3. 98 




4. 91 


. .55 


5. 94 


. 79 


7. 07 




8. 30 


1. 77 


9. 62 


2. 41 


11. 04 


3. 14 


12. 57 

gullies; how to control and reclaim them 33 

top of the inlet to the outlet end of the pipe would be 8 feet. In 
the first column in Table 1, under Drainage area in acres, find 25, 
then follow the line across the page to, the right to the fifth column, 
which falls under three heads at the top of the table. First no 
spillway round or over the dam; second, storage above dam, surface 
area one-half acre at level of top of inlet pipe; third, 8 feet drop. 
The number in the fifth column is 2.2, which means that the pipe 
through the dam should have an area of 2.2 square feet. In Table 
2 it is found that an 18-inch pipe has a cross-sectional area of 1.77 
square feet, and a 21-inch pipe 2.41 square feet. A 21-inch pipe 
should be chosen, since no smaller standard-sized pipe has the 

required area. ■ n ^ 

Where several drop-inlet soil-saving dams are built m a gully, the 
outlet pipe for the upper dam should be chosen as explained above. 
The size of the outlet pipe for the next dam below will depend upon 
several governing conditions: (1) If the storage above the upper 
dam and the additional watershed area drained by the gully between 
the dams is negligible, the outlet pipe for the lower dam should be 
of the same size as for the upper dam; (2) if the storage above the 
upper dam is negligible and there is a large additional watershed 
area* between the dams, then the size of the outlet pipe should be 
chosen from Table 1 for the total watershed area above the lower 
dam; (3) if there is considerable storage above the upper dam and 
a negligible watershed area between the dams, the pipe for the lower 
dam might be smaller than for the upper dam, yet on account of the 
difficulty of ascertaining just how much smaller the pipe could be, a 
safer practice would be to use the same size of pipe for both dams ; 
(4) if there is considerable storage above the upper dam and a large 
watershed area between the dams, the outlet pipe should be chosen 
from Table 1 for a watershed equal to the sum of the watershed area 
between dams and a certain part of the watershed area above the 
upper dam, depending upon the reduction in flow effected by the 
upper dam storage. It is impossible to say just what part of the 
upper watershed should be included, since hardly any two cases 
would be similar, but this information can be obtained from an engi- 
neer after an examination of the watersheds and the dam sites. 

The waterway through the dam may be a pipe or a concrete box. 
Standard vitrified clay sewer pipe can be obtained up to 36 inches 
and concrete pipe up to 48 inches in diameter. Where a cross sec- 
tion greater than that of a 36 or 48 inch pipe is required a concrete 
conduit of the required cross-sectional area can be built. 

Where the outlet pipe is extended down the gully as an underdrain, 
a very good practice since it prevents erosion at the outlet and in 
the gully below, a somewhat larger tile would be required than that 
indicated in Table 1. The size of such a tile should be determined 
by an experienced engineer. 


Before work is begun, a plan should be decided upon for the 
reclamation of the entire gully. Too often a small section is 
reclaimed in a way which will not fit into any later scheme for the 



reclamation of the whole gully. Work should begin at the upper 
end, where head erosion is going on. This should be stopped by 
building an. overfall of brush and straw, as has been described, by 
constructing a flume to conduct the water into the gully without 
erosion, or by the diversion of the water from the head of the gully. 

Next, plans should be made for filling the gully. If it decreases 
gradually in depth toward the lower end and terminates in a wide 
shallow depression, a number of low temporary dams can be used. 
If the gully terminates in the side of a deep drainage channel, how- 
ever, the lower end can not be filled by a low dam, and a high one 
must be built where the gully enters the channel. Unless conditions 
make it necessary to use high dams, low dams should be built, even 
though more of them are required to reclaim the gully, since the 
cost will be less and low dams are much less subject to failure. 

Often the erosion of soil from the watershed is very slight, and a 
number of years would be required to fill the gully. This is espe- 
cially true where the watershed is in pasture, meadow, or timber. 
In such cases a series of dams of the overflow type should be built, 
so that some silt will be caught above each one, or a dam may first 
be built at the lower end of the gully and other dams built later in 
succession above, after the gully is partly filled in. The side slopes 
of the gully should be plowed in, so that farming operations can be 
conducted in and across the gully. 

Some gullies occur in the natural channels of fields and have 
large drainage areas, while others occur on the slope of a hillside 
with very small drainage areas which are not well defined. Gullies 
of the latter type may be entirely filled and then prevented from 
washing out by proper cultural methods or by terracing. Gullies 
with large well-defined drainage areas can not be entirely filled, since 
it is necessary to leave a waterway large enough to carry off the 
water. A very common mistake is so to reduce the size of the 
waterway by filling in the gully that the drainage water overflows 
its banks; this often proves disastrous to reclamation works. The 
size of the waterway that should be left can be judged from the 
high-water flow in the gully. 


In reclaiming the whole length of a gully a series of dams is 
built, the distance between the dams depending upon their height 
and the slope of the gully. The less the slope of the gully or the 
greater the height of the dam the greater may be the distance be- 
tween the dams. Usually the dams should be so spaced that the 
fill that accumulates to the top of one extends to the foot of the next 
above. A dam will cause a fill that is higher at some distance above 
than at its foot. The fall of the surface of the fill in the gully will 
not much exceed 6 inches in 100 feet, and in computing the distance 
between dams so that the fill will extend from the top of one dam 
to the foot of the next this rate of fall has been assumed and values 
for Table 3 were computed accordingly. The table gives the dis- 

gullies; how to control and reclaim them 35 

tances between dams ranging from 2 to 10 feet in height in gullies 
with falls ranging from 2 to 20 feet in 100 feet. 

Table 3. — Distances between dams in gullies for dams of various heights and gullies 

of various bottom slopes 

Bottom slope of gully 


2 feet in 

5 feet in 

10 feet in 

15 feet in 

20 feet in 


100 feet 

100 feet 

100 feet 

100 feet 

100 feet 

Distances between dams 





























































Sometimes there are contracted sections in gullies that are natu- 
rally suitable for the location of dams. Under such circumstances 
it may be desirable to disregard the spacing as given in the table and 
build the dams high enough to conform to the spacing naturally sug- 
gested. With the actual distances between the dams determined, the 
required heights can be taken from the table. 

As a general rule it is cheaper and more satisfactory to reclaim 
gullies with low rather than with high dams. A low dam costs con- 
siderably less and requires less care and attention than a high dam. 


Secretary of Agriculture Arthur M. Hyde. 

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t ration. 

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