Page 74 - GRIHA Manual Volume IV - Introduction to National Rating System
P. 74
Building planning and construction 65
# Do not let water stagnate in the collection chamber since this will slow down the recharge of
water.
# Repair cracks in the ferrocement tanks (storage) if any.
Water storage vs groundwater recharging
The decision whether to store or recharge water depends on the rainfall pattern of a particular
region and a number of parameters such as the following.
# Size and nature of the catchments
# Site conditions like rainwater outlets, drains, flow direction, availability of space
# Rainfall intensity and pattern: unimodal or bimodal rainfall
# Geology: type of soil or rocks
# Hydro-geology: groundwater level and porous strata
# Dependence on municipal and groundwater sources: number of dry days and scarcity days
# Possibilities of using harvested water
# Cost-effectiveness
For example, in places such as Bangalore and Mizoram where there is rainfall throughout the
year, barring a few dry periods, one can depend on a small size domestic water tank for storing
rainwater, since the period between two spells of rain is short. On the other hand, in dry areas like
Delhi, the rainfall occurs only for three or four months of the year and water collected during the
monsoon has to be stored throughout the year. This means huge volumes of storage containers
would have to be provided. Hence, if the substratum is not rocky and underground water table is
not very high, it is more feasible to use rainwater to recharge groundwater aquifers rather than store
it. However, the selection between storage or recharging or both is a very site specific issue.
GRIHA speciic information
Objective
To utilize the treated wastewater and rainwater for various applications (including groundwater
recharge) where potable municipal water is normally used to reduce the load on both the
municipal supplies as well as the sewerage system and to improve the groundwater level.
21.1 Commitment
In order to achieve the above objective, following needs to be done.
21.1.1 Provision of necessary treatment of wastewater for achieving the desired composition for
various applications. Here, wastewater usage refers to both blackwater and greywater.
Treatment of blackwater and greywater separately and appropriate selection of the
system is an extremely site-specific issue and need to be done carefully.
21.1.2 Implement rainwater harvesting and storage systems depending on the site-specific
conditions. All necessary steps to prevent possible contamination of groundwater by
rainwater harvesting should be taken (design requirements as per the Central Ground
Water Board). This is a mandatory requirement.
21.1.3 Reuse the treated wastewater and rainwater for meeting the building water and irrigation
demand.
21.1.4 Recharge the surplus water (after reuse) into the aquifer.
# Do not let water stagnate in the collection chamber since this will slow down the recharge of
water.
# Repair cracks in the ferrocement tanks (storage) if any.
Water storage vs groundwater recharging
The decision whether to store or recharge water depends on the rainfall pattern of a particular
region and a number of parameters such as the following.
# Size and nature of the catchments
# Site conditions like rainwater outlets, drains, flow direction, availability of space
# Rainfall intensity and pattern: unimodal or bimodal rainfall
# Geology: type of soil or rocks
# Hydro-geology: groundwater level and porous strata
# Dependence on municipal and groundwater sources: number of dry days and scarcity days
# Possibilities of using harvested water
# Cost-effectiveness
For example, in places such as Bangalore and Mizoram where there is rainfall throughout the
year, barring a few dry periods, one can depend on a small size domestic water tank for storing
rainwater, since the period between two spells of rain is short. On the other hand, in dry areas like
Delhi, the rainfall occurs only for three or four months of the year and water collected during the
monsoon has to be stored throughout the year. This means huge volumes of storage containers
would have to be provided. Hence, if the substratum is not rocky and underground water table is
not very high, it is more feasible to use rainwater to recharge groundwater aquifers rather than store
it. However, the selection between storage or recharging or both is a very site specific issue.
GRIHA speciic information
Objective
To utilize the treated wastewater and rainwater for various applications (including groundwater
recharge) where potable municipal water is normally used to reduce the load on both the
municipal supplies as well as the sewerage system and to improve the groundwater level.
21.1 Commitment
In order to achieve the above objective, following needs to be done.
21.1.1 Provision of necessary treatment of wastewater for achieving the desired composition for
various applications. Here, wastewater usage refers to both blackwater and greywater.
Treatment of blackwater and greywater separately and appropriate selection of the
system is an extremely site-specific issue and need to be done carefully.
21.1.2 Implement rainwater harvesting and storage systems depending on the site-specific
conditions. All necessary steps to prevent possible contamination of groundwater by
rainwater harvesting should be taken (design requirements as per the Central Ground
Water Board). This is a mandatory requirement.
21.1.3 Reuse the treated wastewater and rainwater for meeting the building water and irrigation
demand.
21.1.4 Recharge the surplus water (after reuse) into the aquifer.
