Some gardeners are fortunate enough to have natural streams running through their gardens. Even a ditch can be transformed into a stream-like feature, so if you already have such an asset, take the opportunity to exploit it to the full.
The major problem with a natural stream is a constant supply of water. In dry summer weather, you need to be sure that it will not dry up if you are planning to use traditional waterside plants. With a ditch this may often be the case, water only flowing freely during winter and spring. Seasonal stream features, such as this, need careful handling and should only be planted with subjects that are tolerant of periodic drying out It is no use fighting such a feature; accept the situation and contrive your planting to produce as natural a waterside look as possible.
If a stream flows freely all year, it will merely need decorating with appropriate planting and perhaps a stone or shingle bed. Small adjustments may also be necessary to improve the way in which it flows.
Remember, however, that only part of the stream is yours; it will belong to someone else at the points where it flows into and out of your garden. This is a very important consideration,. especially if you anticipate making alterations to its flow rate, which can have an effect both upstream and down-stream. Not only should you consult the owners of neighbouring properties, but also any local or rivers authorities. This also applies if you wish to take a backwater or pond off the stream, although once filled and settled, this is unlikely to alter the flow rate at all.
THE ARTIFICIAL STREAM
Most gardeners who want a stream, however, have to create it themselves, using the same methods as when constructing a pool. The main virtue of an artificial stream is that you have complete control over the flow of water. The disadvantage is visual, since it has to begin and end somewhere. Naturally, an artificial stream will be a recirculating feature, but it must be laid out so that it appears to have a purpose. Apart from the careful plotting of its route, skilled planting must be employed if you are to integrate it satisfactorily inlandscape.
Unlike a natural stream, an artificial stream can flow where you want, and specific planting niches can be created. Water levels can be planned, and the ideal conditions for a variety of aquatic species guaranteed. Make sure that you consider all the possibilities, and plan the construction of the feature very carefully in advance.
A LINED STREAM
A liner is easy to disguise and offers a flexible method of construction. Accurate excavation will be necessary if the liner is to be left exposed, but if rocks are to be incorporated into the edge and pebbles used to cover the stream bed, this will not be quite so critical. However, a fall is vital in both cases, and this should not exceed 30 degrees if the stream is to be effective. This can be achieved in the same manner as when installing pre-formed units.
As with any feature that relies on a liner, all sharp objects that might puncture the material must be removed from the excavation. Then spread the normal layer of damp builders’ sand along the stream bed and up the sides. A fleece underlay can also be employed for a stream, as it will be quite easy to put in place.
If the stream is short, it may be possible to obtain a suitable single length of liner, hut where there are to be variations in level or elaborate curves and arcs, it will be easier, if not essential, to use several separate sheets. These must always be laid from the pool hack to the stream source, ensuring that there are generous overlaps in the direction of flow. Where possible, these should be arranged to coincide with shallow drops orso that the end of the downstream section of liner will be above the water level for that part of the stream.
The liner must be secured at the edges with either soil or rocks, and it must always remain higher than the stream’s maximum water level, otherwise seepage into the surrounding ground will occur. Another form of edging can be made by filling hessian bags with soil, rather like sand bags, then planting them. The plants will soon colonize the bags, producing an attractive, natural-looking marginal or boggy edge.
A lined stream offers wonderful opportunities for creative designs with rocks. If positioned carefully, these can be used to modify the flow of water, producing a variety of effects.
MAKING A LINED STREAM
1. Excavate the stream bed to the finished size and line with builder’s sand, having removed any sharp stones, sticks or other objects that may puncture the liner.
2. Position the liner carefully, ensuring that there is sufficient overlap at the joints and the edge. It is important to smooth out any wrinkles and to ensure that any folds are significant.
3. The edges of a natural looking lined stream can be disguised with bags of soil, which can be planted with trailing plants to link the surrounding garden with the water.