Title:
Silt terrace erosion permanent prevention
Kind Code:
A1


Abstract:
The present invention is directed to a new and useful labor saving method of constructing Λ-shaped dam structures to retain silt in farm field intermittent watercourses by utilizing 10″ and 2″ black plastic drainage tile.



Inventors:
Nolan, John T. (Iowa City, IA, US)
Application Number:
10/459214
Publication Date:
12/16/2004
Filing Date:
06/12/2003
Assignee:
NOLAN JOHN T.
Primary Class:
Other Classes:
405/15, 405/107
International Classes:
E02B3/04; (IPC1-7): E02B3/04
View Patent Images:



Primary Examiner:
LAGMAN, FREDERICK LYNDON
Attorney, Agent or Firm:
John T. Nolan (Iowa City, IA, US)
Claims:

As my invention, I claim:



1. A silt terrace erosion permanent prevention dam structure utilizing 10″ diameter and 2″ diameter black plastic drainage tiles in lieu of dirt filled woven plastic fabric sacks.

Description:

B. REFERENCES

[0001] U.S. patent documents cited: U.S. Pat. No. 6,322,289 B1 November 2002 Nolan

C. FEDERAL SPONSORED R&D

[0002] None

D. MICROFICHE APPENDIX

[0003] None

E. BACKGROUND OF THE INVENTION

[0004] Soil erosion in farm field gullies is a major problem for farmers. Until recently, there was no low cost method of abating the damage caused by the natural erosion of water coursing such fields.

[0005] The construction of Λ-shaped dam structures with dirt filled, non biodegradable plastic sacks as described in the process called STEP, U.S. Pat. No. 6,322,289, Nov. 27, 2001, is a solution to this problem. However, it is a labor intensive method. By substituting 10″ black plastic drainage tile for the dirt filled sacks it saves time and labor and there is vastly increased strength and durability. The improvement was not readily obvious at the inception of the concept of the patent for silt terrace erosion prevention.

F. DESCRIPTION OF PRIOR ART

[0006] Black plastic drainage tile is commonly used to drain subsoil water and it is buried in the ground throughout the field. It is durable, reasonably inexpensive and generally available for such placement. However, no previous construction of a farm-field gully dam structure using drainage tile is known.

[0007] It is the object of the present invention to provide an alternate method of constructing silt terrace erosion permanent prevention dams which are more durable and less time and labor consuming to put in place, and which retain the silt trapping features of the STEP process.

G. SUMMARY OF THE INVENTION

[0008] The object of the invention is accomplished by placing a Λ-shaped 10″ black plastic drainage tile, secured by anchors in the gully. The length of each leg of the Λ-shape is determined by the distance from the Apex to each side bank. The Λ-shape is obtained with the use of a 90 degree angle coupler. A 2″ plastic drain tile is placed beneath and along the downstream exterior of the 10″ Λ tile to baffle erosion by falling water. Each open end of the Λ leg is closed with an end cap and stabilized with a dirt filled sack.

[0009] As with the dirt filled sack STEP structures, water flowing over the 10″ tile is drawn to the center and away from the side banks. Water held upstream in the temporary pool, deposits silt. The water is slowly evacuated from the temporary pool down through the 2″ drain tile, thereby reducing scouring of the stream bed below.

H. BRIEF DESCRIPTION OF DRAWING

[0010] FIG. 1 represents an overhead view of the silt terrace erosion permanent prevention tile dam structure.

I. DETAILED DESCRIPTION

[0011] A cavity is dug along the thread of the stream bed for a 2″ drainage tile (1). Excavated dirt is used to fill woven plastic sacks (7).

[0012] Upstream ends of two 10″ diameter drainage tiles (Λ legs) (3) are fixed into a 90 degree angle (4) and the Λ thus formed is placed in the ditch with the Λ pointing upstream. The length of the Λ legs are determined by the width of the gully at the site. End caps (5) are fixed at each downstream end of the 10″ Λ. Dirt filled sacks are placed over the ends and packed against the side banks of the gully to prevent side bank erosion.

[0013] At the exterior base of the 10″ tile Λ a length of 2″ drainage tile is placed to baffle erosion by falling water (2).

[0014] The entire dam structure is secured with “J” shaped re'rods (6). One “J” re'rod is driven into the stream bed to anchor both the 90 degree angle and the 2″ baffle tile at the apex of the Λ. Another “J” shaped re'rod is driven at the downstream inside end of each Λ leg to pin the ends of the Λ and the dirt filled sacks.

[0015] Water flowing downstream (8) will pool above this dam structure and will occasionally flow over the 10″ drainage tile dam to the thread of the stream bed below. Water which pools above the dam (9) will be slowly evacuated through the 2″ drainage tile and will deposit silt and build up the silt terrace to the adjacent farm field level and eventually restore the grass strip and promote contour farming.