GB2510638A

GB2510638A - Flood control schemes

Info

Publication number: GB2510638A
Application number: GB201302440A
Authority: GB
Inventors: Raymund Sapak
Original assignee: Individual
Current assignee: Individual
Priority date: 2013-02-12
Filing date: 2013-02-12
Publication date: 2014-08-13
Also published as: GB201302440D0

Abstract

A flood control scheme uses a turbine, in-line pump or other device (10, figure 3) located at a point 7 in a river 1 or watercourse to increase water flow downstream 6 of said point and lower the height of the surface water upstream 5 of said point. The turbine, pump or other device may be attached to a temporary support or to an existing bridge (9).

Description

S

A FLOODCONTROLSCI-IEME

This invention relates to a flood-control scheme.

There are a variety of schemes in use today that are used to control flooding in rivers and watercourses as a result of prolonged or heavy rainfall. These are designed mostly to contain flood waters within raised sections of river banks using permanent or temporary structures or there are schemes that divert flood water into temporary catchments or into alternative watercourses. The notion of this invention is to use a system that coutd temporarily improve the efficiency of a river or watercourse acting as a drainage system by energizing one or more sections along its course.

The principal idea of this invention is to lower the height of the surface water level in rivers or watercourses upstream of a point by increasing their water flows downstream and consequently increase the dynamic storage capacity above their natural steady-state conditions. In this invention, this is achieved by putting energy into the rivers or watercourses by using an energizing source, referred to herein as an Energizer', for example a turbine, an in-line pump or a device that can be used to increase the flow at that particular point in a downstream direction. [The design of these particular devices is beyond the scope of this inventioni. This action to energize the rivers and watercourses above their natural steady-state condition will be referred to heein as energization' and would begin a process of draining water from the upstream side of the energizing installation.

Figure 1 shows a schematic sectional representation of the surface water levels along part of a river or watercourse before and during energization. The river 3.

flows in the direction shown above the river bed 2 and below the top of the riverbank 3. In steady-state conditions the surface water profile 4 is stable and the water flow upstream, q1 at point 5, has the same flow downstream, q2 at point 6. Their corresponding heights of the surface water levels, h1 and h2, would also be the same [assuming same parameters apply at each location].

When energization occurs between these two at a point 7, the additional flow U from the energizing source increases the flow downstream such that at point 6 q2 now becomes the energized flow q2' and is equivalent to q2 and a combined, i.e. q2' = q2 + 0. Consequently, there would be an increase in the height of the surface water level h2 to h2'. By continuity of flow the upstream flow q1 at point S has now been reduced to a flow q1' such that q1' = q1 -0 and a corresponding reduction in the height of the surface water level h1 to h1'.

The change in the surface water profile 4' would reflect the energized state.

Notwithstanding the increase in the height of the downstream surface water level, it is envisaged that the additional flow U would continue to flow downstream owing to its momentum from energization and its natural progress due to the gradient of the river bed, rather than flow back and impede the, upstream. flow. The potential to reduce the upstream surface water levels in both pre and post flooding is apparent. In pre-flooding, a reduction in surface water levels and a corresponding increase in the dynamic storage capacity of a river or watercourse could reduce or negate the impact on any flood bulge making its way downstream towards the energizing point.

In addition, the potential to increase the dynamic storage capacity of the river at a location has a time element and thus earlier intervention could potentially increase this capacity. Energizing the flow in instances of post-flooding could potentially speed up the drainage of the upstream watercourse in attempting to assist relief for flooded areas.

It is envisaged that a number of Energizers are temporarily installed at one or more designated locations prior, but not exclusively, to any flood event that is likely to cause a breach of a river or watercourse.

The Energizer will require an electrical supply either from a mains connection or from a generator.

The Energizer will require structural support. This could be achieved by attaching it to a temporary support or as more likely the case an existing bridge. Bridges are usually found within towns and villages built adjacent to watercourses and where, the control of river flood wate.r is. usually most acute.

These locations usually benefit from having electrical mains supplies close by and hence facilitate the possibility of a hook-up for a power supply.

Figure 2 is a schematic plan view of an Energizer installation using a river bridge.

Figure 3 is a schematic elevation of an Energizer installation using a river bridge.

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Figure 4 is a schematic section through the Energizer installation to indicate the potential reduction of river levels between two Energizers working in tandem.

Figure 2 and Figure 3.show an installation using Energizers at three points on a bridge. Such an arrangement is for illustration purposes only as the numbers, fixing arrangements and locations of the Energizers will depend on engineering factors which will best be determined. during the planning stages... The, river 1. is flowing in a direction indicated, confined between river banks 8, traversed by a three-arched bridge 9. The position of each Energizer 10 is held in position below the river surface 4, and above the river bed 2, using a guide-bar 11.

Electric connectors 12, run from the Energizers along the bridge to an electric mains hook-up 13. Figure 2 shows the Energizers positioned on the downstream side of the bridge. This favoured position (as opposed to the upstream side) will reduce the possibility of erosion of the river bed around the bridge piers due to the increased turbulence generated by the energizers.

Figure 3 shows two potential arrangements for the Energizer/guide-bar installation as either a cantilever 14, or with the toe of the guide-bar resting on or fixed to the river bed 15 in. order to resist potential moment forces on. the bridge from the thrust generated by the Energizer on the guide-bar.

In some instances it may be an advantage to position Energizers to the upstream side of the bridge. Figure 4 shows Energizers working in tandem in both upstream 16 and downstream locations 10 in order to exploit the potential. of a reduction of the heights of surface water levels between, them.

In Figure 4, the relative velocity of the water flowing under the bridge v1, is greater than the velocity of the upstream water approaching the Energizer v2.

Continuity dictates that there is a corresponding reduction in height of the surface water level (h2 -h1) between the Energizers. This coul.d be of particular significance when dealing with rising water levels that meet the bridge soffits.

As water levels submerge the bridge soffits, a significant back-up of the upstream water level occurs as the bridge now impedes the river flow which in turn increases the risk of flooding. Reducing the surface water heights by a process of energization in order to maintain free-flow of water beneath the' bridge soffit may delay or prevent river water backing up at the bridge locations. -

Claims

CLAIMS1. The principal idea of this invention is to lower the height of the surface water level in rivers or watercourses upstream of a point by increasing their water flow downstream and consequently increase their dynamic storage capacity above their natural steady-state conditions.. In this invention, this is achieved by inputting energy into the rivers or watercourses by using an energizing source, referred to herein as an Energizer, for example a turbine, an in-line pump or a device that can be used to increase the flow at that particular point in a downstream direction. This process will be referred to herein as energization'.
2. The energization as in Claim 1 wherein in pre-flooding conditions, a reduction in heights of the surface water levels and a corresponding increase in the dynamic storage capacity of a river or watercourse in order to reduce or negate. the. impact on any flood, water making its way downstream towards the energizing point.S
3. The energization as in Claim 1 wherein which has the potential to increase the dynamic storage capacity of the river at a location has a time element and thus earlier intervention could potentially increase this capacity.
4. The energization as in Claim 1 wherein of the flow in the instances of post-flooding could potentially speed up the drainage of the upstream watercourse in attempting to assist relief of flooded areas.
5. The energization as in Claim 1, Claim 2, Claim 3 and Claim 4 is such that the energizers will require structural support. This could be achieved by attaching it to a temporary support or as more likely the case an existing bridge having suitable fixings and electrical connections..
6. The Energizer as claimed in Claim 1 wherein reducing the heights of the surface water levels by a process of energization could be exploited in order to maintain free-flow of water beneath the bridge soffit and hence may potentially delay or prevent river water backing up at the bridge locations. /