TIPS & TECHNIQUES
  In Florida, having a pond or waterfall on your garden railroad is a natural. Our excellent climate lends itself to these features since we do not have to worry about ice & snow. Most people have a pond, which is either freeform with a rubber liner, or pre-formed. I have found my best source of matreials and information on ponds is at my local Lowe's store. They have many books on the subject, and I would recommend you read "Quick Guide to Ponds and Fountains" which is available at Lowe's, before you get started. It covers all areas of pond building and maintenance, including a section of plants and fish. I am not going to go into great detail on how to build ponds, streams, and waterfalls here, but will only touch on some points and lessons learned by myself and others. Much of the information comes directly from the book.  One of the most important rules of pond building is to have compacted fill on the bottom and sides of the pond. Water weighs 8 pounds per gallon, so a small 50 gallon pond will weight 400 pounds when filled with water. If the bottom and side fill is not firm, it will give way and your liner will stretch and possibly leak.
     Whether you have a pre-formed shell, or have free-formed your pond, you will want to conceal the rim with rocks once the pond is filled. Allow your rock to overhang the pond edges by 1 to 2 inches. Do not allow the full weight of the edging to rest on the pond rim because it may damage the pond walls. If necessary, build up an area with mortar around your pond to help support the rock. Some people wash and pour fine river rock into the bottom of their ponds so that the bottom can be seen. Check with a pond supply dealer as to the type of rock that is best suited for pond use, since some types gives off chemical compounds that may kill plants or fish.  Not only are streams and waterfalls attractive features in a pond, but they also aerate the water, providing additional oxygen for fish and pondlife. Waterfalls can imitate the streams and cascades found in nature, or they can be formal in design. Building a successful watercourse is a matter of trial and error. To create the effect you want, you will have to experiment with different sizes and shapes of rocks, as well as their placement. You should design your waterfall so that all the water falls directly into the pool or catch basin to minimize water loss. A mixture of rock, including flat stone for water to flow over, can be used and worked with until you get the effect that you want to achieve. Waterfalls look best when large overhanging rocks are used to make the lip of the falls. If you direct your water flow between two large boulders, you will get a gushing effect. Some people use a piece of clear acrylic plastic to produce a wide curtain of water. 
    Streams are very easy to build. Natural streams are usually a series of short fairly flat sections separated by low falls or cascades. You should make your stream bed as level as possible so that it will retain some water when the pump is turned off. A drop of 1 inch for every 10 feet of distance is all that is needed to make a stream flow downhill. There is no need to dig a deep trench to make your stream flow. To increase the speed of your stream, bring the banks closer together; for a more leisurely current, move the banks farther apart. Remember when laying out your stream that a meandering course will look more realistic than a straight one. Placing large rocks inside the stream bed will create rapids, and placing smaller stone and pebbles will create a rippling effect. 
    Pump sizing should be done by the experts. I know that Lowe's has a chart in their pond department that will help in your selection. You should also have a filter on your pump intake to catch debris even if you do not intend to have fish in your pond. Beware of the pond stores that want to sell you a $300 pump when you do not need one. I have a waterfall that leads to a river which empties into a pond, and got by with a $60 submersible pump from Lowes. This waterfall is 3 feet high, the river is 18 feet long, and the pond holds about 70 gallons of water. If I hadn't done some research, I would have paid the pond store here in Tampa $300 for the pump they said I needed. My pool pump costs that much, and I have a 15,000 gallon pool !
    Remember here in Florida we have to deal with evaporation. A waterfall will speed up evaporation, so make provision to refill your ponds at regular intervals. I bought a timer at Home Depot that hooks up to the hose bib near my layout. Every day at 5:00 PM the water runs and refills my pond/river/waterfall for 15 minutes so that my water level is kept where I want it.
    Remember, do your research, ask questions, and have fun
 
PONDS AND WATERFALLS