AU598257B2 - Method and installation for stormwater discharge regulation - Google Patents

Description

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PATENTS ACT COMPLETE SPECIFICATION

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98257 (Original) FOR OFFICE USE 7 24{ $7/c c7 Class Int. Class Application Number: Lodged: Complete Specification Lodged: Accepted: Published: Priori ty: Related Art: 'ir arftaneats madie wd~r Sectkin 4,, i~11i~ D~iZThC1 t~ r printing. I 'It I Ott

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I I *q'are of Applicant: SWINBURNE LIMITED Address of Applicant: Actual Inventor(s): Address for Service: John Street, Hawthorn 3122, in the State of Victoria, Commxonwealth of Australia DAVIES COLLISON, Patent Attorneys, 1 Little Collins Street, Melbourne, 3000.

Complete specification for the invention entitled: "METHOD AND INSTALLATION FOR STORMW4ATER DISCHARGE REGULATION" The following statement is a full description of thislinvention, including the best method of performin4 it known to us I i -2- "METHOD AND INSTALLATION FOR STORMWATER DISCHARGE REGULATION" This-invention relates generally to stormwater discharge regulation and particularly to methods and installations for control of the same.

O tt* One particular application of the present invention 5 relates to the control of stormwater drain-off in 0440 urban or suburban environments such as home sites and it will be convenient to hereinafter describe the invention with reference to that particular application. It is to be understood, however, that this is not to be considered as a limitation as to the scope of the invention.

In recent years, the practice of redeveloping 0* 0 existing building sites having or proposed for a single dwelling thereon with multiple dwellings such 15 as home units or town houses has increased considerably.

This had led to several problems in handling the increased run-off of stormwater from the site owing 6to the reduced amount of garden area for absorbing -stormwater and the greater roof area and concreted areas resulting from the increased number of dwellings.

In fact, in many instances, the existing main piped drainage systems cannot cope with the relatively large increase in run offs.

o 00 0000 e 0 o o o 000 ffiO 0** o rrarr 3- 1 2 3 4 6 7 8 9 11 12 13 14 15 16 17 18 19 21 22 23 24 26 ,27 28 29 31 32 33 It is an object of the present invention to provide an improved method and/or installation for controlling stormwater drain-offs.

According to the present invention there is provided an installation for controlling the flow of stormwater from a site to a main drainage system, the installation comprising a primary stormwater storage or collection ;sone for receiving stormwater from the site, the primary collection zone including an outlet therefrom, a discharge control line having one end operatively connected to said outlet of said primary collection zone and having a discharge outlet at the other end operatively connected to the main drainage system, said discharge control line comprising a plurality of sections operatively connected together with junctions between adjacent sections, the flow direction between adjacent sections changing at the or each said junction so that the flow at each said junction is impeded thereby dissipating energy.

Preferably the volume flow rate through the control line is maintained below 8 L/s. It is also preferable that the velocity flow rate is maintained at or above The primary collection zone may comprise a pit disposed beneath the ground -having said outlet adjacent the lower edge thereof. Furthermore the primary collection zone may also include an above ground storage zone comprising a recessed area communicating with the pit via a grate.

Preferably a pit is provided at each junction between the sections of the control line. Furthermore a pit may be provided at the discharge outlet of said control line to control the effective pressure head between the storage zone and the discharge outlet.

00 0 0 0 O 0 0 0 0000 00 00 0 0 0 0 900329.aruspe.029,72447cl, L- i IL, Va 00 00 0 049 o 00 0 00 o Vaa 00 0*00 00#60 0 0 0o Qo o o aoe a 0 00 0~ Preferred embodiments of the invention will hereinafter be described with reference to the accompanying drawings in which: Figure 1 is a plan view of an example installation according to the present invention; Figure 2 is a plan view of another installation according to the present invention; and Figures 3a, 3b, 3c and 3d are side elevations of pits which can be used in the installations.

Referring to Figure i, there is shown a typical building site which comprises two dwellings 1 and 2 in the form of home units each having a garage la and 2a. The roof cover is indicated by phanton lines lb and 2b. A driveway 6 is provided at one 15 side of the building site providing access to the road 14. Stormwater from the gutters is delivered via downpipes 8 to a primary collection zone 11 via pipes 20 and 21. Stormwater from the driveway 6 is collected in pits 16 and 17 and from there it 20 is transferred to primary collection zone 11 through delivery pipe 42. The primary storage/collection zone 11 comprises a below ground pit 12 and an above recessed area 13 which is in communication with the pit 12 via grate 15. The pit 12 is best seen in Figure 3d. The primary collection zone 11 has an outlet 19 which delivers the stormwater to the control discharge line 20. The control discharge line comprises a plurality of pipe sections 21, 22, 23 and 24 interconnected by junction pits 25, 26 and 27 (see Figure 3b). The control discharge line has a discharge outlet 28 which delivers the stormwater to a control pit 30 (Figure 3c) which in turn discharges the stormwater to the main drain system via line The installation of the present invention has the effect of inducing friction to the fluid flow through the system which at least in part limits the volume flow rate and/or flow velocity of the stormwater to or below a desired level. This arrangement of the control discharge line provides for a relatively long discharge control line so that the stormwater flow rate from the outlet to the discharge outlet is reduced considerably. The friction may also be induced by roughing of the interior of the discharge control line or the use of corrugated or otherwise formed pipes. Preferably, PVC pipes such as UPVC are used although it will be appreciated that other forms of piping could be utilized. It is also preferable that the discharge control line is arranged so that it adopts a relatively low gradient.

It is preferably that the volume flow rate is maintained at below 8/Ls and more particuarly 4 L/s.

As mentioned above, it is also preferable that the pipe forming the discharge control be a nominal diameter e of from 90mm and up to 150mm. Preferably velocity a ,flow rate is maintained above The length of the discharge control line will s it generally be greater than 10 overall and up to 250m depending upon the pipe diameter and volume flow rate.

Figure 2 illustrates a second building site wherein like reference numerals have been used to indicate certain of the features described with reference 1 30 to the embodiment of Figure 1.

As illustrated, the site comprises two dwellings 1 and 2 having garages la and 2a with roof sections lb and 2b. In this particular arrangement, the primary collection zone 11 is formed by a significant part of the driveway 6 (shaded area) and comprises two pits 12 and a recessed above ground collection/storage zone 13. The stormwater is transferred from this I -6zone to the discharge control line 20 which comprises oan 2. sections 21 and 22 interconnected by junction pitcs and The head control pit 30 is disposed at the end thereof where the stormwater is discharged to the main drainage system via line 40. The shaded area 13 forming the above ground storage zone is sloped so that stormwater is directed towards ts 12.

In this particular installation a small auxiliary drain 46 is provided.

It will be appreciated that the installation of the present invention provides a simple yet effective arrangement for retaining stormwater on the site and discharging it at a controlled rate. By such a system relatively larger diameter pipes can be used thereby reducing the possibility of blockage. By dissipating the pressure head of the system the r outflows can be maintained at a desired level.

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Claims (9)

1. An installation for controlling the flow of stormwater from a site to a main drainage system, the installation comprising a primary stormwater storage or collection zone for receiving stormwater from the site, the primary collection zone including an outlet therefrom, a discharge control line having one end operatively connected to said outlet of said primary collection zone and having a discharge outlet at the other end operatively connected to the main drainage system, said discharge control line comprising a plurality of sections operatively connected together with junctions between adjacent sections, the flow direction between adjacent sections changing at the or each S said junction so that the flow at each said junction is impeded thereby dissipating energy. 440

2. An installation according to claim 1 wherein the volume flow rate through the control line is maintained below 8 OL/s.

3. An installation according to claim 1 or claim 2 wherein the velocity flow rate is,-maintained at or above

4. An installation according to any preceding claim wherein said primary collection zone comprises a pit disposed beneath the ground having said outlet adjacent the 0'L lower edge thereof.

An installation according to claim 4 wherein said primary collection zone further includes an above ground storage zone comprising a recessed area communicating with the pit via a grate. 900329,araspe.029,72447cl. iYU~ I.

6. An installation according to any preceding claim wherein at each junction there is provided a pit.

7. An installation according to any preceding claim wherein there is further provided a pit at the discharge outlet of said control line to control the effective pressure head between the storage zone and the discharge outlet.

8. An installation substantially as hereinbefore described with reference to the accompanying drawings.

9 The steps or reatures disclosed herel any_iambinat--en ~eeof. a 9*4 I~ 4 1 4 ItL I P t Dated this 30th day of April, 1987 SWINBURNE LIMITED By its Patent Attorneys DAVIES COLLISON 4 t >LS