Tag: Water Harvesting

We interrupt the ongoing Chain of posts on E@BS to introduce our ‘Q & A’ column.

Our segment on Cleantech One [published: June 18, 2018] left us with 2 questions. We address one of them today –

Q) Integration with Green has positive effects on micro-climate and energy loads. However, landscaping has associated water and maintenance costs. There are also issues of insects that may not always be welcome in an urban/ strictly controlled setting like that of laboratories. What do you think about this?

A) Water and Maintenance Costs

Water use can be optimized and maintenance can be reduced by adopting certain simple measures. Some of the following have been adopted by our case-studies, specially Park Royal Hotel [published June 25th, 2018]. These measures also help buildings gain points for LEED certification categories – Water Efficiency, Sustainable Sites.

Reduction of Need (Water and Maintenance)

• Selection of Plant Species – Native plants that are local to the site are adapted best to existing conditions. They are thus hardy and require little to no maintenance. Many species can also survive, without any external irrigation.
• Rainwater Harvesting – Storage, treatment an recycling of rainwater for landscape irrigation helps reduce the requirement for Potable water use. In Park Royal, rainwater from upper floors, irrigates plants on lower floors by gravity.

Supplemental measures

• Non – Potable water – If additional water is needed, then non-potable water recycled from site or outside, can be utilized. For example in Park Royal Hotel, recycled wastewater called NEWater is used for additional irrigation needs.
• Drip Irrigation – If supplemental irrigation is required, then drip irrigation is an extremely efficient option. Compared to overhead spray irrigation (efficiency 50-70 per cent), drip irrigation can provide water use efficiencies of greater than 90 per cent. There are multiple other benefits of this type of irrigation which make it an indisputable choice. Various small villages, farmers and projects in India are benefiting from this technology. Some benefits include –
  • Efficiency – There is reduction of  evaporative losses and as water is delivered through pipes, to the plants as they need it.
  • Yield – Farmers in the states of Andhra Pradesh (Anantapur district, Chilli Crop) and Tamil Nadu (Tuberose flowers) in India for example, have seen crop yields double by adopting drip irrigation. This is possible since water along with fertilisers or required chemicals can be delivered to the plants ina precise manner, thus improving plant health.
  • Weeds – Weeds are reduced since the area between plants is not irrigated.
  • Runoff – Runoff , Erosion and related Pollution is prevented.
• Sensors – Landscape areas could have rain sensors, that signal to turn off irrigation, when a minimum level of rainfall is achieved (d).

B) Insects

Insects or pests can be attracted to areas of vegetation and water. While all insects are not harmful, and many are extremely helpful and necessary for the ecosystem; they may not always be welcome in an urban/ strictly controlled setting like that of a laboratory. Let’s look at some ways to deal with this issue –

Pests around water features

Pests specially mosquitoes can be a dangerous problem around water features. Some steps that could be taken to guard against this are-

• Design water features deeper than 2 feet, since larvae prefer shallow water bodies.
• Use fountains or waterfalls, which increase circulation of water and reduce stagnant water.
• Natural predators like dragonflies and back-swimmers help get rid of mosquito larvae. Care should be taken to avoid broad spectrum insecticides, which could kill these helpful creatures.
• Remove organic debris, which is food for larvae – Pond Skimmers are useful contraptions for larger water bodies. For smaller water features, use pond skimmer nets. Pond spikes are good for preventing algal blooms.

Pest repellent Plant species

Another simple way is to choose plant species that naturally repel certain pests. This helps avoid the use of harmful insecticides and pesticides, that have other dire consequences. Some low maintenance species to choose from are –

• Lavender – This plant has a lovely fragrance for humans. However, it repels mosquitoes, insects and smaller animals like rabbits. It is a tough drought-resistant plant and does well in warmer climates.
• Citronella Grass – It has a lemony scent and is a common ingredient for mosquito repellents. It is a low maintainence plant and only requires a sunny spot in the ground in warm climates.
• Marigolds – Their smell deters not only mosquitoes, but also aphids,  whiteflies, squash bugs,   thrips, tomato hornworms, mexican bean beetles. They flower annually and are easily grown in pots.

References/ Additional Reading:

• Drip and Micro-Spray Irrigation
• USGBC LEED Credit Library –Water Efficiency, Sustainable Sites