Picking Out The Spillway Stones
When at the stone center, start by picking out mostly flat rocks to construct the waterfall. Select one larger and thicker flat rock for the base of the waterfall and several other larger flat rocks for the tiers. For the rest of the structure a mixture of sizes and shapes is fine. The rocks used in the waterfall, that will come into contact with spilling or trickling water, should always be angled slightly forward so that the moving water moves in the right direction: towards, and into your pond!
The idea behind selecting spillway rocks for a cascade design is to choose rocks that are most likely to channel the falling water in the precise direction in which you want it to go. In addition to seeking out relatively flat rocks with sharp edges, see if you can find rocks that are slightly cupped. Occasionally you'll come across flat rocks that curl up ever so slightly at the edges, leaving a depression in the middle. The natural channel in such rocks will be greatly advantageous for the creation of the spillways in your cascade design.
Load your rocks up or arrange to have them delivered, and now you're ready to head over to the pond supply store!
Calculating Water Volume
Before choosing a pump and filter for your pond and waterfall, it's a good idea to calculate the volume of water in your pond. This is not absolutely necessary for you to do, but the measurements in the equations below will be useful to your pond store professional. You don't have to be exact with your measurements, just close.
Rectangular Pond: Length in feet x width in feet x depth in feet =cubic feet. Example: 10' L x 6' W x 2' D = 120 cubic feet x 7.5 gallons = 900 gallons
Circular Pond: 3.14 (1/2 diameter in feet x 1/2 diameter in feet) x depth in feet = cubic feet. Example: If your the diameter of your circular pond (from one side to the other) is 10 feet, and the depth is 2 feet, the equation would look like this: 5' W x 5' L x 3.14 = 78.5 x 2' D = 157 cubic feet x 7.5 gallons = 1,177 gallons.
Free Form Shapes: Break the pond down into a series of rectangles and circles and figure the volume of each area separately, then add the volumes together.
NOTE: Each cubic foot contains 7.5 gallons of water, so always multiply the total number of cubic feet times 7.5 to determine the total number of gallons. Write down the total volume of water your pond contains. And remember, you don't have to calculate water volume. If you have the basic measurements as to width, length and depth of your pond, this will be enough information for your pond store professional.
Plumbing For Your Waterfall
First, you will want decide the effect of your waterfall. This will help you determine the amount of water flow you need and the size of pump and filter that will be necessary to create the desired effect. Some like to create a raging waterfall while others prefer the trickle effect. The plumbing for either choice is quite simple and you should have no problems handling this yourself.
Pumps are available in both submersible and external (out-of-pond models). Reputable water garden suppliers have charts and other information available that can help you select the best model and connecting equipment for your purposes. For the smaller pond, a submersible pump is the most economical. Depending on the size of the pond, a filter and even a skimmer may also be incorporated.
Pumps come in a confusing array of models and sizes. Below is information that will help you determine what size of pump you will need for your pond or water feature.
If you find the following confusing, don't worry, just take recommended measurements to your pond supply store and a professional can help you figure out what type and size of pump will be required.
Pumps are sized by gallons per hour (GPH) output at one foot of lift or height. Larger capacity pumps are rated by horsepower (hp). Manufacturers offer charts that break down the power of each size pump according to incremental heights of one foot. Some companies label pumps by GPH while others assign letter or number designations that require cross-referencing to charts.
It is recommended that the water in a basic pond be turned between 1/2 to 1 times per hour. A 500-gallon pond should have at least a 500 Gallon Per Hour pump. When sizing a pump for a pond there are a few other considerations.
- How high will the pump have to lift water?
- Will there be a fountain?
- Will there be filters?
Important Other Measurements To Write Down Before Visiting The Pond Store
Estimate the vertical height from the top of your pump to the top of your waterfall or stream and write this measurement down. Add another foot of height (or lift) for every 10 feet of hosing you will be using and write this measurement down. If you plan to have a stream a general rule of thumb is to figure your stream/waterfall requirement as 150 gallons per hour per inch width of the spillway or channel. For example, if your stream or waterfall spillway will be 10 inches wide, you will need a pump that produces a flow of 1500 gallons per hour (at whatever combined height of the feature and another foot of height for every ten feet of hosing to get there).
This may sound a bit confusing so just write down all the measurements (heights and widths) you can think of so that when you consult with a professional he/she will have these measurements to assist you in determining the size pump you need.
NOTE: It is best to order a pump that will more than handle your needs as pumps come with valves that allow you to reduce the amount of flow.
Submersible Pumps are placed directly in the pond. They are free of distracting noise and can be used to drain your pond when necessary. These pumps do have a disadvantage. The pump seal can rupture, sending oil coolant into the water. This can prevent surface gas exchanges, thereby endangering your fish. We would recommend the new magnetic-drive pump, which avoids the use of coolants. They are more expensive to buy but are far less expensive to operate.
All of these variables reduce the amount of flow, which could affect water quality and clarity.
Don't let any of this technical information about pumps scare you away! A few simple measurements you take can provide your pond supply source or local pond consultant with the information needed to assist you in choosing the right pump. Just remember this: DO NOT skimp on the pump!