BEGINNER’S GUIDE TO BUILDING STREAMS AND WATERFALLS: Part 2 - Estimating Stream and Waterfall lining materials and other things

STREAM AND WATERFALL LINING MATERIALS

Streams and waterfalls for the more grand water gardens are most effective and reliable when waterproofed with a concealed flexible liner. However having said that, many of the most well known contractors in theButyl and Firestone rubber are my favourite materials for lining streams and water falls. country, renowned for the enormous rockscapes they create, just depend upon reinforced concrete without a liner. The mere weight of 5 or even 15 tonne stones that are often used, would not only puncture the strongest liner but would make it exceedingly difficult to place the stone. Bentonite is also used for large displays but it must be well covered with stone to prevent it from washing away.
For the smaller displays, the preformed units you can buy off the shelf are becoming more realistic year by year and are increasingly becoming an attractive option. Installation of these, although fairly straight forward, will be covered in another small article. My preferred option is for flexible liners and in particular rubber or butyl especially for waterfalls. With both of these products, cement sticks and holds facing stone to the material whilst it is going off. Although it does not make a life long permanent seal, it helps when building up tall rock faces on precipitous waterfalls.

TO ESTIMATE THE STREAM LINER LENGTH

Length on the horizontal x (2 x the height of the head). The width is governed by the standard widths of liner. A 5ft wide liner, for instance would produce a stream with 2ft 6ins header pools with 9-12ins outlets. A 10ft wide liner gives you 4-6ft headers with possible 2ft wide waterfalls.

BLOCKWORK

If you making your stream or waterfall through made up ground, perhaps the soil excavated from the pond, you will need a skeletal framework of blockwork. The quantities of blocks depends on the length of the stream and the steepness and the fall. If the ground is very steap, the blocks may need to be laid on top of each other so that it would not just be enough to run down the sides of the stream or waterfall. However get at least that number in to start you off. For estimating purposes, blocks are roughly 18inches by 9inches by 4 or 6inches.

STONEWORK AND ROCKERIES.

Another Brian Aughton waterfall stream and rockery at the Tatton Park Flower ShowRockery: You can estimate the quantity of stone for a rockery by multiplying the height by the width in feet and taking each square foot as accounting for 1 cwt or 50kilos. This is the same for estimating the rockery surround and the stream face. One of the reasons rockeries are so out of favour is because of the scar stone quarries make on our landscape. Also much of the weathered stone that people had preferred to use was pillaged from the beautiful landscapes of the ever-diminishing limestone pavements of the Northern counties of England and Eire.
In estimating stone for the stream, think in terms of either of the quantities required for edging and facing the inside and a large part of the base area. Small gaps can be filled in with pea gravel and large gaps and corners can be filled with pebbles.

It is possible to buy reclaimed rockery stone or field-stone picked out of fields on farmland. Good looking rockery stone is therefore incredibly expensive, and is probably best used as individual stones as features in themselves, rather like the Japanese may use them in groups of two or three. If you are trying to create a rock bank that is self-supporting and all but the face of the stone is going to be buried and then hidden with plants, large pieces of ‘block stone’ straight from the quarry are perfect. Well-weathered water worn stone can be a nightmare to fit together convincingly.

However, even cheap ‘block stone’ can be expensive, mainly due to the delivery costs, and if it is stored, the room it takes up that could otherwise be used for some more valuable product. Therefore, for the sake of expense and appearance it must be a local stone. What is more, if it is a stone that looks nothing like any local stone then it will perpetually look out of place.

ELECTRICITY SUPPLY.

THE CABLE OR CONDUIT? The costs of installing an electricity supply can easily exceed the costs of all the actual units and pumps that it is intended to run if the feature is a long way from the mains supply. SoProfessional installation of electrical power to a large fountain display. figure this out in advance.
You can choose to have either a single armoured cable to supply the electricity or to run an ordinary mains cable through an electrical conduit. The size of armoured cable you choose should be capable of supplying 13amps worth of power at 240volts. It should be laid at a depth of half a metre set in a 15cm deep bed of clean chippings with a plastic tape warning strip lying on top. Check these specifications out with an electrician as they could change any time. It is possible to have the cable pinned to a wall in a protected situation like the unobtrusiveness of being under capping stones or sills. A 2 core cable is suitable for most pumps since the armoured protection is used as an earth wire. As long as the pump is modest, there is no reason why an other pump (say a filter pump) and an Ultraviolet clarifier might not run off the same cable if the power can be shared out at a weatherproof fused switch box, but they must all be a fairly low ampage. Some manufacturers are producing fairly cheap junction/fuse boxes, with an array of switches if you choose, that can function in this situation on a ‘Do-it-yourself’ level.
For more serious use of power, 3 core cable can be used for running perhaps a pump and some other item, because both items can be wired in using the armour as an earth and they can share the neutral wire. 4 core is a popular choice for the individuals who might be keen to run a pump for a waterfall and fountain, a separate one for a biological filter system and still have one spare for a U/V clarifier or pool lights. Where the armoured cable joins up with the cable to the unit (e.g. the pump) you want power for, you will need a junction box with the correct waterproof fittings to ‘translate’ the armour cable to the ordinary weatherproof cable of the unit. Budget for this.

The box contains a time swith and each pump has its own trip switch
The alternative method is to lay a conduit down to carry ordinary weatherproof domestic cable. There are special flexible electrician’s conduiting, but for long runs, outdoor alcathene or plastic water pipe will do. 25mm bore plastic waterpipe can take several cables. The trick is to lay the conduit down with a electrician’s ‘draw cable’ or piece of stiff garden wire already in it, because it is much easier to thread anything through a long length if you are able to jiggle it about a bit a you push the end down. Once this is down through the conduit, you now have the tool installed to pull through your normal type of weatherproof mains cable. Then you can bury the pipe with its either end rising up to the necessary junction boxes or switch boxes at each end.
You will have to consider where you want the switches. Having the switches near the pool makes life simpler, because there is less cable to run outside. As with the armoured cable above, one cable can run the lot. If you were to consider running several cables through the conduit it is virtually impossible to thread cables through when there is already some cable there, so always ensure there is a ‘draw cable’ in the conduit so that you can draw a new cable through. Then each time you pull through another cable ensure there is another piece of wire attached to the cable you are drawing through. This will be the ‘draw cable’ you use to draw up the next cable.
When attaching a cable to a ‘draw cable’ or wire, make a loop in the wire that is definitely not going to come undone.
Thread one of the core wires of the cable through the loop. Twist it up with one of the other wires completely and tape them all tightly against the side of the cable with insulation tape.
Test the join forcefully before you attempt to draw the cable or cables through.
If there is any part of the water garden project that you really need to be qualified to do, then installing the electrical supply is it. Even if you feel confident in doing it the bulk of the installation yourself it when you come to connect it to your domestic supply, at least get it checked by a professional. All the electrical supply to outdoors should be on a separate ‘loop’ to your domestic supply so that if any fuses it does not affect your home supply.

THE JUNCTION BOXES AND MAINS CONNECTIONS. SWITCHES AND RCD’s

It must also be protected from blowing the whole domestic shebang by a 30ma RCD trip switch that will shut things down virtually instantly if there is any trace of power ‘leaking to earth’. This would occur as soon as any dampness found its way into a connection or electrical unit or if any current found a way out into the environment. These can seem expensive at the time, but nowhere near as much as freezer full of meat and frozen food that would conk out when the house end of the electrics blew.
At the pool end, the junction box can be as mentioned in the armoured cable description or it can be a series of weatherproof plugs in a weatherproof box. If you are going in for any units that run on a 12volt supply, like a small pump or lights then a junction box large enough to hold the transformer plus the any plugs or switches would be useful. This could be fitted into a wall or hidden away with the filter system. With this in mind, if you are considering installing cheap 12 volt lights for outdoors or underwater, try to ensure that they have their own trip switch since they are much more prone to short circuiting in bad weather than most other outdoor electrical items.
All these electrical items come in different several levels of expenditure. The DIY market in garden centres and aquatic stores caters for the requirements of most people quite adequately, but the products have a limited life and durability. If you have a professional electrician install equipment that does the same job, you will find it to be considerably more expensive and it looks completely different, however in time it will prove its value as with minimal maintenance it continues to serve its purpose.

PUMPS and the relationship to FITTINGS AND PIPEWORK (see forthoming aricle on MOVING WATER for more details and suitability of the pumps for what purpose.)

When considering the pipe work that will carry water to a water feature, stream or waterfall, always go for the largest practical diameter hose with the least number of fittings. This allows the pump to perform at its most efficient. But for every 10ft in length of hose it will lose between 60 and 100 gallons per hour in power. The easiest pipe to use is the type of flexible pipe sold at the aquatics store. Now that ribbed pipe is available it is even more flexible but is a significant expense in the total. Also do not forget the hose clips and any extra fittings.
The performance in pumping vertically (the head) varies considerably from one make of pump to another. Manufacturers in their advertising literature and on their products’ boxes, generally give details on individual pump performances. If the pump performance is in a curve on a graph or on a table, then go for a pump that has the performance you require right in the middle of the graph or the table. In this way you will be going for more power than you think you will need. That spare power will be easily taken up if you want to run a fountain from the waterfall pump, which would reduce its performance by at least 30%. Also consider whether you are incorporating a biological filter and an ultra violet clarifier in the feed to the stream or waterfall, or is it going to be separate. These will slow the water flow quite considerably mainly because of the fittings (hose tails and joints etc) involved in these items of equipment.
When comparing pumps in terms of their performance, also take into account their running costs. It is possible that what you gain on the costs of the pump, you very quickly lose on the running costs. This is particularly important if the pump is running a biological filtration system, since this will be running 24 hours a day. If the costs are not stated on the box or in the manufacturers literature you can get a mental ‘yard stick’ from the Wattage of the unit.
Another mental ‘yard stick’ is the guarantee, which will tell you roughly what the manufacturer considers the life expectancy of the pump will be. And quite frankly, if the pump has only got a one year guarantee, I would look elsewhere.

EXTERNAL PUMPS.

If you are in the realms of the grand masters here and you are contemplating a very large ‘puddled’ pond or a vast waterfall or hugely wide cascade, you may be considering an external pump. The specifications of both the volume and the height to which the external pumps can shift water is virtually unlimited. They have a long life expectancy and are easily repairable in relative comfort and for this reason they are relatively expensive. They do tend to hum, so need housing in a sound proof but well ventilated box. Some will also need an arrangement for priming them if they are turned off.

BIOLOGICAL FILTERS.

You may be considering incorporating a filtration system in with your waterfall or stream and may with to have this at the head. I don’t necessarily recommend this since the filter system needs to operate all the time day in day out and you will not necessarily want the stream to be doing that. However the head of the stream is often a very convenient place to hide a filter. Anyway since it is time to be thinking of installing power, naturally filters and ultra violet clarifiers and indeed anything that is going to need electrical power should be added to the equation now so that safe access to sufficient power is available up the water garden. Biological filters clean the pool water by filtering the organic matter and algae from it as it move through the various types of media. Also micro-organisms that build up in the media actually digest this organic matter, breaking it down to its constituent chemical ingredients. If a pool biological filter is required, a FILTER PUMP capable of pumping a certain amount of solid matter up to the filter without clogging up is necessary. Then for it to be effective, it must be capable of turning over half the volume of the pool per hour with the pump situated as far away from the filter as possible. Biological filters usually need a month to get fully operational in a digesting capacity. Since they function with the aid of micro-organisms, which depend upon oxygen, a continuous flow of oxygen rich water is essential. This means they must be operating continuously, 24hrs a day. If the filter is incorporated in the supply to a waterfall or stream, having the stream running 24hours a day may not be desirable particularly in cold weather, although it may be desirable to have the filter gently turning over the surface water of the pool if it is not too cold. For this reason it is best to have the filter system as a separate entity from waterfalls or fountains. Suffice it to say that if you are budgeting for a biological filter at this stage, you may as well add the price of an extra pump and an ultra-violet clarifier, and don’t forget the necessary fittings and switches.
Biological filters are even more efficient at keeping water clear when there is an ULTRA-VIOLET CLARIFIER unit (UVC) incorporated in the system. Both units need to be installed in a place where they are easily accessible.
The ultra-violet clarifiers are matched to specific flow rates and filter sizes and depending on your pool volume, you will have a suitable size of filter to choose from, which will relate to a pump capable of delivering the required volume of water via a UVC with the relevant power or wattage.