Slad Brook Flooding 20 July 2007 A preventable Flood?

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1 Cllr Chas Townley Slad Brook Flooding 20 July 2007 A preventable Flood? A report into the the impact of the Slad Brook flooding on 20 July 2007 and an examination of potential solutions.

2 On Friday 20 July Stroud endured continuous rainfall most of the day with an estimated rainfall of 60 mm (which in old money equates to nearly 2 ½ inches). This resulted in extensive flooding in Slad Road, Uplands and further upstream in the area of The Vatch and New Mills. This followed an earlier flood in June. Slad Road from Gloucester St Slad Road from Park Gardens New Mills, Libby s Drive ` New Mills Libby s Drive` Vatch (water is just below letterbox) Vatch An access road becomes a river

3 Taken together the impact of these three areas of flooding has significant impact on the well being of a large number of residents and businesses. Either because of direct impact of flooding on their property or indirectly because the flooding has interrupted services like utilities, roads etc to their community. The number of residents directly affected is estimated to be between 100 and 200. Whilst the immediate effort of the emergency services and public authorities was rightly focussed on relieving the distress and danger caused by the flooding there is a longer term strategic issue of what action could be taken to prevent this flooding and what action could have been take as part of development to improve the river flow within the Town Centre. Historical Development in area of Slad Road The map below is based on the Tithe Maps for Stroud and Painswick in 1839 and This shows the stream (now culverted) running down from the Grove (now Hawkwood College) and Slad Brook running as an open stream

4 This OS Map below from 1882 shows that by this time the streams have been culverted.

5 Historically, before the urban development of Stroud spread into Merrywalks, the area between the Maltings and the Old Police Station contained a badly polluted Mill Pond ( Badbrook ), which would have enabled the river in flood to spread out and cause limited impact to property because their was very little property in the area. Since that time the mill pond has gone and the river has been culverted. An area for investigation is whether action should/could have been taken as part of the Cinema development to improve the flow of the river at this point. Historical Flooding Problems It is clear that the flood problems on the Brook are not new. The local Catchment Flood Management Plan (EA 2007) lists a series of flooding events. This is probably an under recording of events affecting the Slad Brook as the list records other events relating to the Frome. July 1907 August 1931 February 2001 August 2004 Gloucestershire Frome severe flooding resulted from intense summer thunderstorms whch mainly affected the Nailsworth Stream and the River Slad Flooding resulted from intense summer thunderstorms which mainly affected the Nailsworth Stream and the Slad Brook (note the Nailsworth flood were 20'' higher than 1820 levels Property affected by flooding... slad brook, nailsworth stream Property affected by flooding... River Frome, Slad Brook and Nailsworth The 1931 flood caused severe damage to Nailsworth (so bad that a Nailsworth flood fund was set up) and the Stroud News/Journal coverage has limited information about other areas. The July 1907 flood was reported in the Stroud News of July 26 which records the storm as starting about 3pm on the Monday 22 July Wycliffe, School Headmaster Mr W A Sibly recorded the rainfall as 2.21 inches with 1 ½ falling between 3.30 and In a long list of incidents the paper reports:- In Slad Road the inhabitants of the low lying cottages had to take refuge in the top stories, the water rising several feet. In some of the houses it rushed in the at the back door and out at the front. One of the affected owners was Philip Ford (who was also an Urban District Councillor and Chairman of the Baths and Sanitary Committee responsible for the town's sewers) His solicitor fired off a stroppy letter to the UDC alleging that for some time past this stream, which is in reality one of the sewers of the Urban District Council, has been a nuisance to him (Mr Ford) and he has given repeated notices to this effect. At the same meeting of Council the owner of 141 Slad Road Mr J Freebury was claiming from the Council for damage to furniture. After two months deliberation SUDC decided it wasn't a sewer and wasn't their responsibility. The Council had carried out an inspection and concluded that the brook was obstructed under the Painswick Inn and sought to get the Brewery to sort the problem out. After further delays the Council decided to treat the blockage of the stream as a statutory nuisance under the Public

6 Health Act In the end the Brewery agreed to meet the costs of clearance with the Council carrying out the work. It is clear that other areas of the brook were also obstructed with the newspaper reporting Cllr Dudbridge (a Lansdown resident) commented about the removal of the wood The cleaning will go on? These are only the preliminary steps? The Surveyor responded Yes. He added that the work was being done by arrangement with the Brewery Company. Later in this newspaper report from the Stroud News of December that the Clerk added that he had also received a number of other letters from riparian owners stating that they would be willing to pay their share of the cost of removing the obstructions Issues from the July 2007 Flood Smartworks At the point where the River enters the culvert beside the Cinema and at the back of Smartworks, the water was flowing well into the culvert, however, the level was higher on the upstream side of the grating, indicating that the flow was impeded by rubbish on the grating. Smartworks Culvert During Flooding After Flooding showing rubbish

7 Section of Stream beside Cinema/Smartworks This two photographs show the section of the unculverted steam as it comes out from under Smartworks. The depth of the water in the first metre or so is much deeper than the remainder of the stream to the grating. This sliting estimated to be as much as 500 mm could have an impact on the culvert to handle the volume of water. Slad Road From Locking Hill towards Slad Road Offices/Factory Opposite Park Gardens (note the stream overflowing the wall at the back of the factory car park) The immediate cause of the flooding at the end of Slad Road may have been caused by the culvert between the bottom of Gloucester Street and Slad Road not having the capacity to take the flow of water. This is also likely to be been worsened affected by the problems at Smartworks, Merrywalks. This section of Slad Road acts as a large holding lake when the brook breaks its bank at this point. This is, in part, because the ground levels have been changed at the Gloucester Street junction meaning that there is nowhere for the water to flow.

8 Culvert under Mr Wilson Copp's Properties This photograph shows a section of the culvert under Mr Copp's property. This is part of the section shown as not covered over in the 1882 OS map earlier in the report. The red circle shows what is believed to be the culvert from the stream from Hawkwood College. The blue line is to illustrate the estimated clearance in the culvert. This clearly indicates that the designed capacity of the culvert is much higher than the available capacity at either Smartworks or at the culvert further upstream. Flooding of properties in this area is reportedly long standing but has tended to affect one or two properties between the Co-op and Locking Hill. Another issue is that extent to which the flooding was caused by blockage in the culvert. It is also likely that the volume of water is affected by changes in the River above this point. Possibly, most recently by the works at the old creamery site. This is discussed below. Culvert Rear of 28 Slad Road - Day after Storm The key issues at this point are wide ranging 1 How to manage the volume of water coming down the brook from further upstream 2 Maximise the flow of water through the culvert 3 Look at ways to increase stormwater drainage from Slad Road into Merrywalks (so that the extent of damage is minimised in the event of flooding occurring) 4 Clearance of culvert and Installation of Grill at start of culvert to prevent rubbish blocking it

9 Streamside During the flood Normal Flow Streamside is an area which has been developed about 15 years ago. As part of this scheme works were undertaken to the brook, which means that the river is contained within in a steep channel which provides good protection for the houses on either side of the brook in this area. The photograph of the stepped weir illustrates the strength of the flow in this area. During the flood it was not possible to see the weir steps due to the strength of the flow. The normal flow shows the very gentle water coming over the steps of the weir. It should, however, be noted that the bottom weir step has an extremely shallow fall, indicating that the lower section is silted. An issue for investigation at this point is whether there is any potential to use the capacity of the channel at this point to hold back the volume of water to assist flood prevention below this point. It is likely that the priority area for this type of work is further upstream. Stroud Creamery The former Stroud Creamery site now being developed as a housing site by Newland Homes has had significant ground works including reconverting the river. The design appears to have protected the site, however, it is possible that the new works may have increased the flow at this point increasing the problems below this point

10 New Mills 1880 s mapping of the Mill New Mills had flooding within the site of the Mill. Historically the area upsteam of the mill was a Mill Pond. This is now a much more narrow channel limited to the river course. Again works upstream of the Mill would provide the opportunity to hold back water in storm situations. Captain Barton s Close Captain Barton s Close is the last development within Stroud (there are however houses overlooking these fields). The development is located well above the flood levels and is therefore unaffected by the current flooding problems The photograph shows the extent of flooding within the field above the close. However, an option at this location could be to develop this area as a balancing lake so that water is stored in this area to allow gradual release of water into the river below this point. This would help to minimise the problems at both New Mills and Slad Road, Stroud

11 The Vatch This view of the Vatch shows the road looking from the Elcombe side of the Valley and shows the water stretching for at least 100 yards. The immediate cause of this flooding is likely to be the capacity of the culvert under the road at this point. However, the capacity of the brook to cope has probably been affected by changes to river. At one time there were a series of mill ponds above and below this site. As with the Captain Barton s Close site it is considered that some form of balancing lake (to hold floodwater back) should be considered for open fields above this site. Upstream of Slad Village This photograph shows the amount of detritus washed down the hill from Slad on the road to Steanbridge Mill and Down Farm, indicating the extent of the water flowing into the brook at this point. Whilst no flooding of property was observed in this area there were obvious signs of the stream breaking its banks and flooding surrounding low lying land. Role of Statutory Agencies Some of the relevant legislation is set out in an Appendix. The Environment Agency

12 Since 2006 the brook has been defined as a main river which means that the Environment Agency is seen as having a primary responsibility for the brook. There is no statutory duty requiring the Agency to maintain the river, there is no statutory duty on the Agency to ensure that anyone else maintains the brook. There is only a moral responsibility and this is something which is clearly wrong and through improved legislation this is something which needs to be addressed. Clearly if the agency chooses to do something it can fund it. The District Council Apart from the upper reaches of the stream the District Council now has no land drainage responsibilities for the main brook. This does not mean that it no longer has any responsibilities. In fact it is the only authority which has a specific statutory duty. Under the Environmental Protection Act 1990 (the successor to the 1875 Act used by the Urban District Council in 1907) can be used to deal with a statutory nuisance. Section 259 of the Public Health Act 1936 defines a statutory nuisance as including any part of a watercourse, not being a part ordinarily navigated by vessels employed in the carriage of goods by water, which is so choked or silted up as to obstruct or impede the proper flow of water and thereby to cause a nuisance. It is unclear whether this continues to apply to a main river. The District Council also has powers to contribute to the cost of works to water courses. Riparian Owners The only people who have a duty to do anything for the repair of the stream are the riparian owners. The Environment Agency and the District Council have extensive powers to enforce riparian owners responsibilities to maintain the river. Conclusion It is easy to dismiss the flood problems caused on the 20 July 2007 as merely the result of the heavy rainfall but as this document notes there are opportunities to reduce the threat considerably by effective management of the watercourse. In the context of the problems suffered in Gloucester, Tewkesbury and higher up the Severn and Avon the problems may not be considered to be great but they have been long standing. Some of these measures can be done immediately e.g. clearing rubbish from the brook to reduce the impact of flooding. in fact the Environment Agency carried out clearance work on Sunday 22 July but there is still a need to look at what can be done to reduce the risk to life and property. Some of the measures will need investment but the relatively modest works required indicate that the cost benefits of some of these works will enable them to be funded very quickly by the Environment Agency, From the perspective of Stroud the most important scheme would be the creation of a balancing lake upstream of Captain Barton Close and further upstream to reduce the downstream volumes to the capacity of the culverting at both New Mills and Slad Road. This would enable the flood risk to be managed much more effectively than at present. The other area for attention is clearly upstream of the Vatch to provide protection to the properties in this area. This is clearly beyond the remit of Stroud Town Council to champion the need for action in this area and will be highlighted to Painswick Parish Council.

13 Appendix Public Health Act 1936 Nuisances in connection with water-courses, ditches, ponds, &c. power of local authority to require culverting of watercourses and ditches where building operations in prospect (1) The following matters shall be statutory nuisances for the purposes of [F1 Part III of the Environmental Protection Act 1990], that is to say (a) any pond, pool, ditch, gutter or watercourse which is so foul or in such a state as to be prejudicial to health or a nuisance; (b) any part of a watercourse, not being a part ordinarily navigated by vessels employed in the carriage of goods by water, which is so choked or silted up as to obstruct or impede the proper flow of water and thereby to cause a nuisance, or give rise to conditions prejudicial to health: Provided that in the case of an alleged nuisance under paragraph (b) nothing in this subsection shall be deemed to impose any liability on any person other than the person by whose act of default the nuisance arises or continues. 262 (1) If a local authority consider that any watercourse or ditch, situate upon land laid out for building, or on which any land laid out for building abuts, should be wholly or partially filled up or covered over, they may by notice require the owner of the land laid out for building, before any building operations are begun or while any such operations are in progress, wholly or partially to fill up the watercourse or ditch, or to substitute therefor a pipe, drain or culvert with all necessary gullies and other means of conveying surface water into and through it. (2) Any question arising under this section between a local authority and an owner as to the reasonableness of any works which the authority require to be executed may, on the application of either party, be determined by a court of summary jurisdiction. (3) Any person who, on any land to which a notice given by a local authority under this section applies, begins or proceeds with any building operations before executing the works required by the notice, shall be liable to a fine not exceeding [F1 level 1 on the standard scale] and to a further fine not exceeding [F2 2] for each day on which the offence continues after conviction therefor. (4) Nothing in this section shall empower an authority to require the execution of works upon the land of any person other than the owner of the land laid out for building, without the consent of that person, or prejudicially to affect the rights of any person not being the owner of the land so laid out. Urban authority may require repair and cleansing of culverts The owner or occupier of any land within a borough or district, or a rural district or contributory place in which section fifty-three of the Public Health Act 1925, was in force immediately before the commencement of this Act, shall repair, maintain and cleanse any

14 Power of local authority to defray cost of, or execute, works relating to watercourses. culvert in, on or under that land, and, if it appears to the local authority that any person has failed to fulfil his obligations under this section, they may by notice require him to execute such works of repair, maintenance or cleansing as may be necessary. The provisions of Part XII of this Act with respect to appeals against, and the enforcement of, notices requiring the execution of works shall apply in relation to any notice given under this section. Note district substituted for urban district by LGA A local authority may, if they think fit, contribute the whole or a part of the expenses of the execution of works for any of the purposes mentioned in the foregoing provisions of this Part of this Act, or may be agreement with any owner or occupier themselves execute any such works which he may be required, or is entitled, to execute. Note local authority for this Act means the District Council unless powers are granted specifically to the County or the Parish/Town Council Land Drainage Act 1991 Powers to require works for maintaining flow of watercourse 25 (1) Subject to section 26 below, where any ordinary watercourse is in such a condition that the proper flow of water is impeded, then, unless the condition is attributable to subsidence due to mining operations (including brine pumping), the drainage board or local authority concerned may, by notice served on a person falling within subsection (3) below, require that person to remedy that condition. (2) For the purposes of this section in its application in relation to any watercourse (a) the drainage board concerned is the drainage board for the internal drainage district in which the watercourse is situated; and (b) the local authority concerned is the local authority for the area where the land as respects which the powers under this section are exercisable is situated; but references in this section to the drainage board concerned shall, in relation to a watercourse which is not in an internal drainage district, be construed as references to the Agency. (3) Subject to subsection (4) below, a notice under this section in relation to a watercourse may be served on (a) any person having control of the part of the watercourse where any impediment occurs; or (b) any person owning or occupying land adjoining that part; or (c) any person to whose act or default the condition of the watercourse mentioned in subsection (1) above is due. (4) No notice under this section requiring any person to carry out any work on land not owned or occupied by him shall be served without the consent of the owner and the occupier of the land, except in a case where it is not practicable, after reasonable inquiry, to ascertain the name and address of the owner or occupier. (5) A notice under this section shall indicate (a) the nature of the works to be carried out and the period within which they are to be carried out; and

15 (b) the right of appeal to a magistrates court and the period within which such an appeal may be brought under section 27 below. (6) Subject to the right of appeal provided by section 27 below, if the person upon whom a notice is served under this section fails to carry out the works indicated by the notice within the period so indicated (a) the drainage board or local authority concerned may themselves carry out the works and recover from that person the expenses reasonably incurred by them in doing so; and (b) without prejudice to their right to exercise that power, that person shall be guilty of an offence and liable, on summary conviction, to a fine not exceeding level 4 on the standard scale. (7) In proceedings by the drainage board or local authority concerned for the recovery of any expenses under subsection (6) above it shall not be open to the defendant to raise any question which he could not have raised on an appeal under section 27 below. (8) Nothing in this section shall affect the right of an owner or occupier to recover from the other, under the terms of any lease or other contract, the amount of any expenses incurred by him under this section or recovered from him by the drainage board or local authority concerned. Drainage of small areas. Note under Section 107 of the Water Resources Act 1991 the Environment Agency (but not a local authority) has Section 25 powers in relation to a main river 18 (1) Where (a) the [F1 Agency] is of the opinion that any land is capable of improvement by drainage works but that the constitution for that purpose of an internal drainage district would not be practicable; or (b) a local authority other than a district council is of that opinion in relation to any land in their area, the [F1 Agency] or, as the case may be, that local authority may, in accordance with the provisions of a scheme made by it or them under this section, enter on the land and carry out such drainage works as appear to it or them desirable. [F2 (1A) Subsection (1) above has effect in relation to land in Wales with the omission of the words other than a district council.] (2) Schedule 4 to this Act shall have effect with respect to the making of a scheme under this section. (3) A scheme under this section must state (a) the works proposed to be carried out; (b) the area to be improved by the works; the estimated expenses (including administrative expenses) of the carrying out of the works; (d) the maximum amount to be recoverable by the [F1 Agency]or local authority in respect of those expenses; and (e) the manner in which the expenses of carrying out and maintaining the works are to be apportioned amongst the lands comprised in the area to be improved.

16 (4) Subject to subsection (6) and (7) below, the amount stated in a scheme in pursuance of subsection (3)(c) above shall not exceed an amount equal to 50 for each hectare in the area to be improved. (5) The following expenses, that is to say- (a)those incurred by the [F1 Agency] or a local authority under this section in the carrying out of drainage works, to an amount not exceeding the amount stated in the scheme in pursuance of subsection (3)(d) above; and (b) those incurred by the [F1 Agency] or a local authority in maintaining works carried out by the [F1 Agency] or, as the case may be, that authority under this section, shall, according to the apportionment provided for by the scheme, be recoverable by the [F1 Agency] or that authority from the several owners of the lands to which the scheme relates. (6) Each of the Ministers shall have power to exempt a scheme from the limit imposed by subsection (4) above if it appears to him that the works proposed to be carried out are urgently required in the public interest. (7) Each of the Ministers shall have power by order made by statutory instrument from time to time to vary the limit imposed by subsection (4) above; but no such order shall have effect unless it is approved by a resolution of each House of Parliament. (8) A scheme made under this section shall be a local land charge