GB2268866A

GB2268866A - Method and apparatus for the irrigation of trees.

Info

Publication number: GB2268866A
Application number: GB9215457A
Authority: GB
Inventors: Malcolm Holland
Original assignee: Individual
Current assignee: Individual
Priority date: 1992-07-21
Filing date: 1992-07-21
Publication date: 1994-01-26
Anticipated expiration: 2012-07-21
Also published as: GB2268866B; GB9215457D0

Abstract

Method and apparatus for tree irrigation in which one or more perforated containers (22) buried in the ground, especially ground with clay sub-soil, are used to collect water from an adjacent rain water collection system (26) during the heavy rain periods and leak water into the ground to feed adjacent trees during drought periods, any overflow from container 22 passing along pipe 28 to drainage system 29. <IMAGE>

Description

Method and Apparatus for the Irrigation of Trees This invention relates to a method and apparatus for the irrigation of trees. The term "trees" as used herein includes shrubs and large hedges and the like.

Trees, especially large trees, can present a danger to adjacent buildings, especially in districts having a predominantly clay sub-soil. During periods of drought, a large tree can draw much of the available water from the clay sub-soil over a substantial area around the tree, causing the clay to shrink. The foundations of any building in or overlapping into the area are thus likely to settle, with resultant structural damage to the building.

Solutions to this problem generally involve cutting the tree down and/or underpinning the building. Removal of the tree is sometimes not possible due to tree preservation orders and in any case may not be desirable. Underpinning a building is expensive and in the case of a domestic dwelling very disruptive to the occupants.

The above-described problem arises in both rural and urban landscapes, but especially in urban landscapes where, additionally, drained concreted and paved areas around a tree can starve the tree of water and cause it to die.

According to one aspect of the invention, there is provided a method of tree irrigation in which a reservoir for water is created beneath the ground surface in an area adjacent a tree from which the tree draws water, and the reservoir is fed with water from an adjacent rain water drainage system which also receives overflow water from the reservoir when the reservoir is full.

The method is especially applicable in ground where the sub-soil is predominantly of clay.

The invention visualises use of one or more perforated containers having a very substantial volume for the storage of water. The container(s) fill during the winter and slowly dispense water into the adjacent clay sub-soil throughout a summer drought, not only to provide water for the tree but also to prevent the clay from shrinking. In the winter, although the container(s) become full, the surrounding clay sub-soil is wet and thus becomes substantially impermeable.

Overflow water from the container(s) then returns to the mains drainage system.

Thus, according to another aspect of the invention, there is provided apparatus for tree irrigation which comprises one or more underground perforated containers buried in the clay sub-soil of the ground adjacent a tree, thereby to form a water reservoir, and a water feed pipe leading from an adjacent rain water drainage system to the reservoir, together with means whereby overflow water from the reservoir is returned to the drainage system.

The water feed pipe may itself serve for return of overflow water, or a separate return pipe may be provided. The requirement for a separate return pipe will in part depend on site levels.

The water feed pipe, and return pipe if provided, will generally be buried in trenches. However, even when a return pipe is necessary, only one trench will sometimes be required.

The rain water drainage system from which water is drawn may be that of an adjacent building. For example, water may be taken from the conventional rain water downpipe. However, the water could be drawn from any rain water drainage system, such as a local authority ground drain or even a ditch.

The reservoir may be formed by a very large single tank, such as a septic tank which is drilled with holes, or by a plurality of smaller perforated containers which can more easily be buried in the ground. Cylindrical perforated containers may be preferred, as holes in the ground for receiving such containers may be drilled with an auger, and extensive excavation is avoided.

The method and apparatus according to the invention are exemplified in the accompanying drawings, in which: Figure 1 pictorially illustrates a house built on clay sub soil and overlapping into an area from which a large tree draws water from the soil; Figure 2 shows a perforated fibre glass tank; Figures 3 and 4, in elevation and plan respectively, show practice of the invention using the fibre glass tank; Figure 5 shows an alternative water container; Figure 6 shows practice of the invention using a plurality of the containers of Figure 5; and Figure 7 shows part of a rain water drainage downpipe equipped with a fitting for supply of water to a reservoir and for overflow back into the drainage system.

Referring to Figure 1, reference 10 denotes a dwelling house building on foundations 12 in clay sub-soil. The house is adjacent a large tree 14, the roots 16 of which draw water from a surrounding area overlapped by the house foundations.

In a period of drought, the tree drains the clay sub-soil of water, causing the house foundations to settle, resulting in structural damage 20 to the house.

Figure 2 shows a plastics or fibre glass septic tank 22, which has been modified by drilling a substantial number of perforations 24 therein.

Referring to Figures 3 and 4, the ground adjacent the tree 14 is excavated, and the tank 22 is buried in the clay sub-soil.

A feed pipe 25 from the roof water drainage system 26 of the house 10 supplies water to the tank 22, and a return pipe 28 returns water to the drainage system 29 and at a point below the feed pipe take off. The feed pipe 25 and the return pipe 28 are buried in one or more trenches.

In winter the tank 22 fills with water and overflow is returned to the drainage system. In summer drought conditions the tank slowly dispenses water to the adjacent clay sub-soil, both feeding the roots of the tree and also preventing the clay from shrinking, so that settlement of the foundations of the house is also prevented.

Figure 5 shows an alternative and smaller perforated container 30, again preferably of plastics material or fibre glass, for forming a water reservoir. This smaller container 30 may be preferred because it can be buried by digging a suitable hole in the ground with an auger, avoiding the need for extensive excavation.

However, as shown in Figure 6, a plurality of such containers 30 are required to be buried in the ground adjacent the tree 32, all fed from a trenched feed pipe 34 and over flowing via a trenched return pipe 36, generally as described with reference to Figures 3 and 4.

Sometimes, site levels will permit the feed pipe also to serve as an overflow pipe. In this case, a fitting 40 such as that shown in Figure 7 may be used in the rain water downpipe of the adjacent building.

This fitting 40 in the downpipe 42 normally supplies water to an underground reservoir through feed pipe 44, but when the reservoir is full provides for overflow of water at the weir 46 back into the house drainage system 48.

It is a significant feature of the invention that its application is concerned with clay sub-soils. It is in this environment that substantial soil shrinkage occurs while, when the sub-soil is wet, it becomes substantially impermeable.

It is to be appreciated that an additional advantage of the invention is that, during summer months, rain water is diverted to the reservoir for subsequent purposive use, rather than going to waste.

The invention is not limited to the feature of feeding the reservoir from the drainage system of a building; in urban heavily concreted and paved areas water can be tapped from the ground drains and fed to the reservoir, overflowing back into the main ground drainage system when the reservoir is full.

It is also to be understood that the invention is not restricted in application to the situation where risk of subsidence of a building is to be minimised. In urban areas especially, large concreted or paved areas can lead to water starvation of trees, which, if they are allowed to die, are subsequently very inconvenient and expensive to cut down and remove.

Claims

1. A method of tree irrigation in which a reservoir for water is created beneath the ground surface in an area adjacent a tree from which the tree draws water, and the reservoir is fed with water from an adjacent rain water drainage system which also receives overflow water from the reservoir when the reservoir is full.

2. A method according to claim 1, applied in ground where the sub-soil is predominantly of clay.

3. A method according to claim 2, employing one or more perforated containers having a very substantial volume for the storage of water, which container(s) fill during the winter and slowly dispense water into the adjacent clay sub-soil throughout a summer drought, not only to provide water for the tree but also to prevent the clay from shrinking, whilst in the winter, when the container(s) become full, the surrounding clay sub-soil is wet and thus becomes substantially impermeable, enabling overflow water from the container(s) to return to the mains drainage system.

4. Apparatus for tree irrigation which comprises one or more underground perforated containers buried in the clay sub-soil of the ground adjacent a tree, thereby to form a water reservoir, and a water feed pipe leading from an adjacent rain water drainage system to the reservoir, together with means whereby overflow water from the reservoir is returned to the drainage system.

5. Apparatus according to claim 4, wherein the water feed pipe may itself serve for return of overflow water, or a separate return pipe is provided.

6. Apparatus according to claim 5, wherein the water feed pipe, and return pipe if provided, are buried in a trench or trenches.

7. Apparatus according to any of claims 4 to 6, wherein the rain water drainage system from which water is drawn is that of an adjacent building.

8. Apparatus according to claim 7, wherein water is taken from the conventional rain water downpipe.

9. Apparatus according to claim 7, wherein water is drawn from a local authority ground drain or a ditch.

10. Apparatus according to any of claims 4 to 9, wherein the reservoir is formed by a very large single tank, such as a septic tank which is drilled with holes, or by a plurality of smaller perforated containers which can more easily be buried in the ground.

11. Apparatus according to claim 10, wherein the containers comprise cylindrical perforated containers, and holes in the ground for receiving such containers are drilled with an auger.

12. A method of tree irrigation substantially as hereinbefore described.

13. Apparatus for tree irrigation substantially as hereinbefore described with reference to the accompanying drawings.