The innovation of products such as Growth Mediums mean that less watering is required as HGMs, BFMs and FGMs work to retain more water for faster vegetation, while binders and tackifiers act as a “glue” reducing seed movement and run-off during heavy rain periods. However, the quality of water used during hydroseeding and hydromulching applications and during the irrigation of grass through its growth period is important to ensure that adequate germination of seeds is reached, along with effective erosion control. Water quality can vary dramatically based on the water source and in some circumstances, can not only be inadequate but even detrimental to your revegetation goals. Of concern is large industrial sites using bore water, such as mining or construction sites, as bore water can be contaminated or be of very poor quality.
Water Quality Issues
A number of issues with bore water exist that may affect your success with hydroseeding or hydromulching. Salinity can cause a build up of salt in the soil, stunting growth or even inhibiting grass germination. Once sodium levels have built up in the soil, chemical amelioration and flushing with fresh water is likely needed to rectify the problem. Such products can be added during spraying and can mitigate the salinity issues; however, over the long term a more suitable water source should be found. A similar problem can be found with a high level of metals in the water which may be of concern on mine sites in particular, although this problem is harder to rectify.
Water with a pH that is too far from neutral (pH 7) may cause grass to grow poorly or not at all as it can cause nutrients to be locked up by the soil. However, even a less severe change from pH 7 can cause binding polymers in the hydromulch itself to not work correctly. This may inhibit its ability to bind the mulch together, affecting its erosion control capacity and can lead to soil and seed wash away. The water pH can be adjusted relatively easily, so it’s important to know if this is necessary.
Ensuring an adequate source of water is important to the success of your hydromulching or hydroseeding project. Bore water may not always be an appropriate source and, if it’s going to be used, care must be taken. Testing your source water to ensure that no significant contaminants are present and that, if needed, soil ameliorants are added to mitigate the effects of salt or pH is important.