Pondstruction - How to build a Native Frog Pond
January 10th, 2018
Carleton Landscaping was asked to build a pond for an existing client this Autumn. There are a couple of questions you should ask before any construction is to be done outdoors. Is it safe to dig? How will drainage be addressed? For this property, there were a couple of challenges for the build that had to be addressed before construction could begin. Currently, there were lots of weeds where the desired pond was to be built. Drainage away from the house in the event of overflow had to be put into the design, as the grade was naturally sloped toward the house. Anytime you dig, it is also important to check for below ground power, water, sewer, and gas lines. In BC, this means calling BC One Call to get maps of the Hydro, Power and gas lines of your property to ensure you don't hit a major gas line when you are excavating your site.
Because your current site may be difficult to visualize your future desired landscaping, having a Landscape design may be practical to have a place of reference. We produced both a site and concept design for this project because of both the drainage and graing issues. It was also important for us to be able to show the homeowner our concept so that they would have a realistic picture of what we were planning on building. A pond can come in many different shapes, materials and sizes, so this ensures proper understanding between both parties.
Our concept plan is a natural character pond built from local sourced boulders, river rock and sand materials. There are a number of wetland native plant species, as well as a driftwood log and shallow rock recesses for shelter and wildlife habitat. There is no pump or filter, and relies on natural rainwater as an ephemeral pond, helping to prevent mosquito breeding.
Site plan with drainage sloped away from the house entrance and the neighbour's house. Important because Vancouver rains so much most of the year!
We also sent in a request to BC One Call to arrange for the proper digging permits. Any time you are excavating, it is proper protocol to inform them of your proposed dig, no more how small the job. At Carleton Landscaping, we take safety seriously and will get permitsfor even small dig sites such as this one. The consequences of not doing this could be the risk of cutting into an underground service with potential for loss of life, personal injury, damage to property, or disruption of a service. It usually takes 3 business days for them to e-mail back with the property maps, as you will receive mail from BC Hydro, Fortis and your jurisdiction city (in this case, City of Burnaby). Once all members confirm the job you are given a ticket to operate, and you have 14 calendar days of placing your request to start excavation activity and your ticket will be valid for a maximum of 30 calendar days from the date your request was placed. It took us 4 days to get our tickets and permitting confirmations from all parties, and then we began site preparation.
Pond excavation is done quick with a pick. We shaped our pond into a kidney bean shape, but it's up to you how you want to design yours.
Make sure that you tamp down the bottom of the pond as flat as you can. Use a tamper. This will help getting the liner down as smooth as possible. You can then add the liner. We use commercial grade 45mm EPDM liner, double layered if possible. Measure out the area of your pond, and add a couple extra feet to the measurement to account for the depth of the pond. Buying extra instead of too little will ensure that you have enough to cover the entire area of the pond. It is easiest to lay out the liner with two people because you want it as flat as possible to the dirt. By filling the liner with water, you can use it's weight to help smooth out any additional creases in the liner.
Once the liner is as smooth as possible, add your base. We chose a Sechelt sand base. After the base is applied, we hold the liner in place with smooth 9-12″ Cheekeye River rock. This height allows the rocks to set into the grade of the edge, as if the pond formed naturally from the rock.
Finishing the design with a driftwood log helps critters exit the pond easily, as well as provide shelter for amphibians or other aquatic creatures. When you are happy with placement, cut along the edges of the liner with an exacto-knife, burying the excess liner underneath the soil to keep it in place. As it is a natural pond, there is no pump or filter, but will simply fill with water during the rainy season. This GREEN choice helps to save costs from having to supply energy to a pump or replace parts in breakdown, as well as save energy and be more sustainable.
The finished installation.
We complemented the look by putting down a layer of 1-1 1/2″ landscaping pebbles long the bottom of the frog pond, as well as high polished charcoal stones for accent. A selection of native submergen and shoreline plants are planted in and around the pond for natural oxygen filtration. We also put in a wood Fibar Bark mulch path for easy access to the pond. The native plants species include Wapato, Cotton grass, Marsh violet, Tufted Hair grass and Lyngbei's Sedge.
The very next day after install, we had our first visitor!
The frog pond is ready for visitors, starting with the neighbour's cat!