THE INGENEER

Newsletter of The Group of Professional Engineers

Volume 2 Issue No: 15 DECEMBER 2014

Jorge Leiria, Director Casais (Gibraltar) Limited, The original order was for 5 units and this was kindly organised for members of the Group to subsequently increased to 9. Each unit com- view the construction of the caissons at the old prise of 18 compartments and is made of rein- Dockyard. The visit took place on Friday 12 forced concrete. They are 30m long by 10m September 2014 at 0900. Those members at- wide and 11.5 m high. They will eventually be tending also benefited from a technical talk and placed at –8 metres depth. powerpoint presentation on the project.

These Caissons will prepare for the reclamation of land at the North Mole area where the new Power Station is to be constructed.

the time constraints of crossing the border with the Gibraltar plant used after 14:00 hrs.

Each Caisson is fabricated in three phases. Phase 1 and 2 works, comprising the construc- tion of the 50cm bottom slab and walls upto a certain height, are carried out in a floating Dock. Because the floating dock cannot touch bottom and due to the depth of water available Whilst one caisson was being cast the rein- the partly finished unit is floated out of the dock forcement fo the next one was prepared. It and moored alongside the wharf for phase 3 took 6 to 8 working days to complete a unit. which is the completion stage. Once completed they were towed out to the Slip-form casting was used which demands detached mole and moored there awaiting good co-ordination to maintain the rate of pour. transport to their final destination. Two batching plants were used, one in Spain and another in Gibraltar, to achieve continuous pour. The one in Spain for the mornings, due to

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Technical Talk on the recent Marine Works at Sandy Bay

Sandy Bay in the 1970s

Emil described the background of the project as follows: Sandy Bay is approximately 400m long. It has never been a particularly wide beach and in the 1970’s the width at the widest point was approxi- mately 20m and only 10m at the narrowest ends. Over the years the width of beach (High Water Level to the back sea wall) was gradually decreas- ing from 10-20m to 5-15m. Between 2008 and 2010 there was a noted in- crease in the sensitivity to storms to the point that the beach became flooded and the beach was ef- fectively lost. This loss of beach created a myriad of problems at the most notable of which were:

On the 6th November 2014 at the Lecture •Trafalgar Bar/ changing rooms – had to be demol- Room of the John Mackintosh Hall Mr Emil ished. Hermida MA BEng (Hons) CEng MICE , Senior •Sewage Pumping Station – had to be relocated Civil Engineer with the Government’s Techni- cal Services Department. •Integrity of sea wall was at risk •there was an overall loss of amenity

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By the Autumn of 2010 there was effectively no beach at Sandy Bay and the then Government de- cided to take action by carrying out a beach replen- ishment programme. Van Oord were contracted to place approximately 43,000 tonnes of sand on the beach. They obtained a dredging licence to extract sand from the sea bed and pump it on to the shore. These works were completed in May 2011. Work carried out by Delft Hydraulics in 2006 sug- gested that the rate of erosion was in the order of 0.1 to 0.3 m per annum, so in a 40 year period this could account for a loss of beach width of between

5 4m and 12m. Given the width of Sandy Bay in 1970 • Design must consider any possible impact this rate of erosion is significant. on adjacent coastlines • The designers must identify optimal hy- The geometry of Sandy Bay suggests that there is draulic boundary conditions and design very little net long-shore deposition on the beach wave conditions from available data although in certain wave conditions sand loss is • Design solution must optimise cost of likely at the ends of the beach ( Longshore drift is a construction process responsible for moving significant amounts of sediment along the coast. This usually occurs in one direction as dictated by the prevailing wind ). In a cross-shore condition the beach is particularly sensitive to sand loss ( cross-shore transport refers to the cumulative movement of beach and near- shore sand perpendicular to the shore by the com- bined action of tides, wind and waves, and the shore-perpendicular currents produced by them). Although the exact causes of the erosion were not identified with certainty the main cause was con- sidered to be relative sea level rise.

In May 2012 the current Administration authorised studies to be carried out to try and find a long term solution to protect and replenish the beach at Sandy Bay. The Design Brief essentially required consultants to meet the following general objec- Various options were proposed and costed but at tives:- the end the preferred option was for a design and • Provide design solutions to achieve a sta- build contract with Van Oord for the construction of ble beach at Sandy Bay groynes at each end of the beach plus the con- • Beach stability and shoreline protection to struction of a submerged breakwater connecting be provided by whatever means consid- both groynes. A Perched Beach would also be pro- ered necessary and could include groy- duced via sand replenishment. nes, breakwaters or other coastal protec- The groynes had to be designed to have the ability tion measures to reduce littoral transport, be able to be “sand- • Identify volumes of sand required tight” to minimise sand losses and reduce incident • Design solutions should optimise marine wave energy and height in order to increase the biodiversity stability of the replenished beach. The submerged • Design solution should be arrived at by breakwater had to be capable of reducing incident numerical modelling wave energy and height in order to increase the

6 stability of the replenished beach. It should be able to withstand the turbulence caused by waves breaking on it in order to reduce the stirring up of sediment landward of the breakwater plus it should be “sand-tight” to minimise sand losses On approval of the scheme and in tandem with the detailed design development by Van Oord an Envi- ronmental Impact assessment was prepared by Amec. The document is a public document which runs to close to 300 page.

The main chapters of the Environmental State- ment were :- • Coastal processes and geomorphology • Marine water and sediment quality • Biodiversity • Traffic and transport • Air quality and climate • Noise • Landscape and visual assessment • Historic Environment • Recreation and socioeconomics

The project was carried out in three phases: Phase 1 – Construction of groynes at each end of the beach Phase 2 – Construction of submerged breakwa- ter – Phase 3 – Sand Replenishment The actual works phase of the project can be di- Following the 45 minute talk there followed an in- vided in to 6 broad steps: teresting questions and answer session. Members 1. Rock and sand delivery and stockpiling at attending partook of the usual refreshments at the the Eastside Reclamation end of the session. The Chairman presented Mr 2. Pre-construction survey works Hermida with a suitably inscribed model of the Rock 3. Mooring basin construction at the Eastside to mark the occasion. Reclamation 4. Groyne Construction 5. Submerged Breakwater Construction 6. Sand Placement

The project started on 10 March 2013 and was completed on 30 June 2014.

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2014-Engineering Heritage Lecture

8 epidemic of 1865 lead to a Sanitary order In Council, equivalent to an act of Parliament in Eng- land, giving rise to the Sanitary Commissioners appointed by the Governor who took responsibil- ity for proper Sanitation and the works to make this possible. Mr Edward Roberts CE sent to Gi- braltar by the Secretary of State for War to pre- pare the necessary plans and estimates for the extra tanks proposed by the Commission

REFUSE COLLECTION AND DISPOSAL

Regular collection of refuse was clearly estab- lished by 1876 with two collections per day in Gibraltar Group of Professional Engineers re- summer and one per day in winter. The refuse cently held their annual lecture on “Engineering was taken to Eastern Beach at the end of Devil’s Heritage”. This year the theme was “Victorian Tower Road. Here a contractor who had a con- Foundation of Gibraltar’s Essential Infrastruc- tract with the commissioners, for removing all ture”. The talk was delivered by Group member bones, bottles, broken glass, tin cans, paper, bas- and past chairman and past secretary Manuel kets, pieces of metal, broken crockery, etc., Perez. found in the material, took charge of the refuse. After sorting the refuse out the remainder was Manolo introduced the talk by saying that the thrown into the sea via a chute. technology developed in Victoria's reign (1837 to 1901) brought a social and economic revolu- tion whose effects are still being felt today. The era saw great developments in engineering and the foundation of essential infrastructure some of which are still being used today.

Essential infrastructure is that basic infrastruc- ture the lack of which would make it impossible for communities to flourish and develop. Re- cently Military Engineers have coined the acro- nym S.W.E.T. as what to concentrate on when rebuilding communities ravaged by war. Sew- The idea of cremating the remaining refuse was age, Water, Electricity (Energy) and Trash. In mooted by Roberts in 1879. In 1884 Captain this talk he touched on Sewage Water and Buckle RE proposed a refuse destructor/ Trash as a colleague will be dealing with the incinerator in connection with works for a new development of Electricity in Gibraltar in next chute. Incineration was started around 1897. year’s Engineering Heritage Event.

The Sanitary Commissioners

A Parliamentary Commission on Barrack and Hospital Improvements was established in 1862 to inquire into the sanitary conditions in Gibral- tar and other British Mediterranean possessions. Its conclusions were scathing; there had been no investment in the public water infrastructure in Gibraltar for 150 years, forcing the civilian population to rely entirely on their own re- sources and ingenuity. This and the Cholera 9 WATER SUPPLIES:

How to be self sufficient for water presented a great challenge. The military had been grasping with this issue and determined to construct more tanks to hold more rain water especially as reserves were needed to provision the navy when ships came to port. In 1856 they con- structed a tank at capable of hold- ing 13650 m3. Also in 1860 the constructed an- other tank at Moorish capable of holding 7900 m3. They derived their water from surface run-off from areas prepared for that purpose. mooted as a possibility by Col Beatson RE in These tanks had two compartments each to en- 1859. The Parliamentary commission also pro- sure that there was always a reserve of water posed this but the shores were so heavily pol- for fire fighting. They were also at the same ele- luted with sewage from the sea outfalls that vation and were connected to each other via a they did not dare pump polluted water to tanks trunk main. The 1865order in council provided where it would fester and be distributed to every for these tanks to be eventually passed on to house. Roberts investigated the fact that the the Sanitary Commissioners for their use in any scheme to provide fresh water.

There were a number of wells in the Southport area. These were then interconnected via culverts to drain into a sump. A pumping station was constructed at the ditch to pump water from wells in the area to the Europa Road tank and Tanks. Mr John Dixon, whilst he was engaged as a contractor in Gibral- tar, suggested the possibility of getting fresh water from within the rock. Following up this suggestion a shaft was sunk in Trafalgar Ceme- water of the Inundation was fresh water made tery from which to drive an adit into the rock. brackish by contact with sea water. The inunda- tion had been drained by the RE’s in 1785 and There was a great need of water for sanitary 74 springs found to be feeding it with fresh wa- purposes so that sewers would be properly ter. Roberts estimated that an average of flushed. An order in Council in 1868 provided for 144,000 gallons per day could be had from this the laying of mains to supply premises and for source. A reservoir was constructed in Landport the flushing of sewers. Pumping sea water was ditch to receive water from the inundation to be

10 pumped up from there to the High Level and owners . {Due to the vulnerability of the wells to Low level tanks. possible enemy action a sea water intake was constructed to supply landport ditch with sea- There were a good number of wells in the North water in the event of hostilities. The foundation Front area. A particular one in the northwest to today’s dual water distribution system was side was used to supply water to shipping. How- thereby established}. ever they did not yield water in the quantities required for a public water supply. Clearly the Water water everywhere but not a drop to drink. nature of the terrain, its continuation into Spain, Something had to be done to ease the lot of the how rainfall was absorbed into the ground and poor civilian population who suffered the want the vicinity of sandstone in the neighbourhood of drinking water most. The Sanitary Commis- indicated that there should be a strong probabil- sioners set about laying additional pipelines from ity of finding a plentiful supply of water. At- reservoirs reserved for drinking water and lead- tempts at boring were carried out but without ing these to public fountain from where water fit much success due to lack of suitable equipment. for dietetic purposes could be bought at a rea- Eventually in 1869 success was achieved. Proper sonable price. The southern compartment of wells were sunk and Boiler house and steam the Moorish castle reservoir was reserved for driven pumps erected to pump the water to the Sanitary Commissioners tanks. By this time the tanks at Moorish Castle and at Europa Road came under the control of the SC. At last they had found a source that would meet the needs of the population provide the key to better sani- tary conditions. Unfortunately by 1875 the water from these wells became brackish. Although the water was not fit for drinking or cooking it was nevertheless ok for other sanitary purposes and so it was distributed as such to every house and payment of a sanitary water rate exacted from fresh water and an area of the rock stripped of vegetation with cracks cemented over was pre- pared to collect rainfall and lead the water to a filter and thence to this tank capable of contain- ing 5.7 MLitres. Between 1898 and 1900 4 reser- voirs were excavated into the rock each capable of storing 5.6 MLitres and 14 acres of the upper rock prepared as a rainfall collection area to sup- ply them.

11 The need to pump water at a time when the for 1885 stated that half a million gallons of wa- main motive power was steam meant the use of ter were sold at 25 centimos per 15 gals (due to coal fired boilers. To produce steam you need cost of fuel), whereas rainwater was sold at 22 water and brackish water from wells were used centimos per 100 gals . Above can be seen the for this. The steam produced once condensed layout of the condensers at the southport ditch provides a pure water. So the next progression bombproof station. In 1897 there were also con- was to use boilers purely for raising steam and densers at Rosia in an area leased from the Ad- condensing this steam in prepared condensers miralty. were the product could be run off to be used for augmenting the supply of drinking water. Very Sewage Disposal soon salt water was used as the source. The Sanitary Commissioners Water Supply Account The first public sewers and storm water drains

12 had been laid from 1815 onwards. However the sewage problem as an opportunity to ex- these drains were usually rectangular culverts plore this source of water. If it was found that with stone flags covering them and laid with flat this would yield a good source of fresh water declivity. In summer, when the only water flow- then his second option for the Main Sewer could ing was the meagre amounts used by the in- be proceeded with. If water was not found then habitants they silted up. When it subsequently the Buckle’s scheme would become the Main rained heavily the obstructions caused the flags Sewer. to lift and leaked their fetid contents every- where. All sewers eventually discharged to sea As can be imagined with so many different and the outfalls were all situated to the west. schemes, each having its own cost and time of The Devils tongue and the extended South Mole execution implications, there was substantial essentially became groynes which trapped this controversy as to how to proceed. A committee effluvia within the coast and especially concen- was appointed to decide on this and it came out trated it in the Naval Yard making working con- strongly in favour of the Europa Point Outfall. ditions there unbearable. Some Ships berthed Works commenced and the main sewer as we at the South Mole had to resort to putting swabs know it today was completed by 1898.. of carbolic in their portholes to try and neutralize the smell. Also a defensive line of breakwaters had been constructed in front of the walls. This left an area of almost stagnant water frequently contaminated with sewage as pipes leaked.

Attempts were made during Victorian days to reduce the amount of sewage flowing out into the shore by diverting most of it via a main sewer to discharge into deep waters west of the South Mole. Various proposals to permanently solve the problems were made By Roberts, Tudury and Captain Buckle. In 1889 Major Hec- tor Tulloch RE , Chief engineering inspector to Arising from the need to ensure adequate falls the UK local Government board was consulted the head of the main sewer had to be at a cer- on the matter. He proposed two solutions. One tain level. This left an area of town situated be- was to adopt Captain Buckle’s scheme in a par- low this level that could not be drained by grav- ticular way and the other was to construct a ity. He proposed that these areas be drained to main sewer, part of it involving tunnelling, to a location where a Shone’s Ejector would then discharge its content to sea near the lighthouse lift it to the head of the sewer. This location was where float experiments indicated that the efflu- also used to pump water to a reservoir located ent would be naturally diluted and dispersed into by the head of the main sewer that would occa- the straits and away from land. sionally empty into the sewer to flush it and keep it free from silting. Below is a City Council- In 1877 Mr Andrew Ramsay, fellow os the Royal drawing showing that the system was still in use Society and Director General of the UK’s Geo- in the 1930s. logical Survey, had been consulted on the hydrogeology of the isthmus when the well wa- ter there turned brackish. He had recommended borings to take place to ascertain whether the Spanish tertiary sands underlay the isthmus as it was likely that these would be water bearing. He had dismissed the possibility of groundwater within the body of the rock being a useful source of potable water. Tulloch disagreed with this and saw in Captain Buckle’s proposal solving

13 At the end of the Talk there was a lively ques- tion and answer session. The talk was very well received by a packed Charles Hunt Room. The event was formally closed by His Excellency The Governor who presented Manolo with a glass model of The Rock on behalf of the Group in recognition of the excellent service he had, and continues to give, to the Group. portunity to have a photograph taken with His All present were then invited to drinks where the Excellency who is always more than willing to debate continued. The committee took the op- support the Group.

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ANNUAL GENERAL MEETING

The Group held its Annual General Meeting at 19:00 hrs on the 2 December 2014 at the Lec- ture room of the John Mackintosh Hall.

The Agenda was as follows: 1. Introduction by the Chairman 2. Approval of minutes of 2013 AGM 3. Secretary’s report 4. Treasurer’s report 5. Election of committee 6. Any other business

The Committee for 2015 was elected as follows:

• Chairman: Mr. D.A. Orfila CEng MIStructE • Vice Chairman: Mr Emil Hermida MA BEng (Hons) CEng MICE • Secretary: Mr. A J Harrison M.Eng • Treasurer: Mr LAS Parody BSc(Hons) CEng MIMechE • Past Chairman: : Mr R J A Labrador MBE, MSc, IEng, FIET, CFIOSH • Committee Member: Mr F X Pons BSc(Hons) CEng FIET • Committee Member: Mr M Perez BSc(Hons), M.Eng, CEng, FICE, MCIWEM; C.Wem • Committee Member: Mr H Pallas BSc, CEng, MIET, MCMI • Committee Member: Mr R Khalilian BSc(Hons), CEng,MIET,MCMI • Committee Member: Mr J Baldachino BEng(Hons) • Committee Member: ir. B. Van Thienen MSc • Co-opted Senior Royal Engineer: Maj Seán F SCULLION RE

After the meeting there was a presentation by Mr Mark Crabtree, MD of International business, Sedna Aire International entitled “Energy earns…or simply burns, the choice is yours”. System, and is widely claimed as the most efficient on the planet.

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A the end of the talk the incoming Chairman, David Orfila, presented the speakers with a suitably inscribed model of the . The meeting was then adjourned to the cafeteria for refreshments. Season’s Greetings

and best wishes for 2015

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