Page 109 - GRIHA Manual Volume II - Introduction to National Rating System
P. 109
Sustainable site planning 101
Figure 7 Water-eficient irrigation
Irrigation schedule
Irrigate with the proper amount of water
To conserve water and maintain a healthy landscape or garden, irrigation should be as infrequent
as possible, and each irrigation should moisten the soil root zone. Frequent, light irrigations result in
plants with shallow root systems that dry rapidly when under water stress. Infrequent deep irrigation
encourages the development of extensive root systems that fully utilize the entire soil profile.
To correctly apply enough water to moisten the root zone without losing excess water to deep
drainage requires an understanding of soils. Soil is much like a sponge that holds water. Once the soil
is moistened, plants are able to obtain water from the soil. As more water is added to the soil, it will
eventually become saturated and excess water simply drains through and is lost to groundwater.
Determination of the quantity of water to be added to soil on each irrigation, in turn, depends on
large part on the texture of the soil. Coarse, sandy soils have rapid infiltration rates, good aeration,
and poor water retention whereas finer, clay-loam type soils have slower infiltration rates and
greater water retention. With turf irrigation it is recommended that the top 25–30 cm of the soil
be moistened at each irrigation. To moisten a sandy soil may require 2.5 cm of water, while a fine-
textured soil may require 5 cm.
The lawn grass requires the same amount of water regardless of soil type. Therefore, since sandy
soils hold less water than clay soils, they must be irrigated more frequently, with smaller amounts,
to meet the plant’s needs.
Efficient irrigation requires uniform application of a known amount of water to the landscape. It
is therefore, crucial to select the optimum irrigation system.
Figure 7 Water-eficient irrigation
Irrigation schedule
Irrigate with the proper amount of water
To conserve water and maintain a healthy landscape or garden, irrigation should be as infrequent
as possible, and each irrigation should moisten the soil root zone. Frequent, light irrigations result in
plants with shallow root systems that dry rapidly when under water stress. Infrequent deep irrigation
encourages the development of extensive root systems that fully utilize the entire soil profile.
To correctly apply enough water to moisten the root zone without losing excess water to deep
drainage requires an understanding of soils. Soil is much like a sponge that holds water. Once the soil
is moistened, plants are able to obtain water from the soil. As more water is added to the soil, it will
eventually become saturated and excess water simply drains through and is lost to groundwater.
Determination of the quantity of water to be added to soil on each irrigation, in turn, depends on
large part on the texture of the soil. Coarse, sandy soils have rapid infiltration rates, good aeration,
and poor water retention whereas finer, clay-loam type soils have slower infiltration rates and
greater water retention. With turf irrigation it is recommended that the top 25–30 cm of the soil
be moistened at each irrigation. To moisten a sandy soil may require 2.5 cm of water, while a fine-
textured soil may require 5 cm.
The lawn grass requires the same amount of water regardless of soil type. Therefore, since sandy
soils hold less water than clay soils, they must be irrigated more frequently, with smaller amounts,
to meet the plant’s needs.
Efficient irrigation requires uniform application of a known amount of water to the landscape. It
is therefore, crucial to select the optimum irrigation system.
