Rainwater Harvesting Potential and Utilization for Artificial Recharge of Groundwater Using Recharge Wells

Abstract

This study devised a practical solution to mitigate urban inundation and artificial recharge of groundwater using recharge wells which is the most viable surface runoff rainwater harvesting (RWH) technique in urban areas. The Rainwater Harvesting Pilot Project at Gaddafi Stadium Lahore was established to deal with urban flooding, artificial recharge of groundwater, and to avoid the mixing of rainwater in municipal sewerage. The study showed that Lahore city has great RWH potential from critical ponding roads that can be utilized to recharge the Lahore aquifer. With that ratio of recharge, the groundwater level can rise to 3.54 ft after every monsoon period if the same recharge wells structure are used, which is a key to groundwater sustainability in Lahore city. Moreover, the maximum recharging capacity of wells was 29.32 m 3 /h with satisfactory performance. Both recharge wells cleared the ponding volume within 3 to 3.5 h after the rainfall stopped. The filter media performance was also favorable with 25%-30% removal of contamination. All the water quality parameters were within the permissible limit against prescribed standards except coliform count that indicated the presence of sewage. In such a case the mixing of charcoal is recommended to shut up the coliform signals. This study identified that RWH using recharge wells is an alternative freshwater supply source for sustainable development of Lahore city and this technique should be the part of Master Planning and Policy Decision of Lahore as a suggestion.Processes 2019, 7, 623 2 of 23 abstraction to fulfil the requirement of the domestic, industrial, and agriculture sectors in Pakistan from last few decades on account of its ubiquitous occurrence, easy availability, and reliability [3]. These qualities have led to its indiscriminate exploitation in dense urban areas of the country such as Lahore without due regard to recharging options. The reckless use of groundwater further aggregates the water scarcity problems, which is a major concern for long term sustainability. To date, more attention has been given to centralized approaches (finding alternative or additional water resources) as compared to decentralized approaches (optimizing water management systems) by water managers and policymakers for fulfilment of sustainable management of freshwater in urban areas. There is an urgent need for development and implementation of water resources management through decentralized approaches such as rainwater harvesting and utilization using artificial recharge structure. This engineering solution for freshwater problems has been proven as a viable option for augmentation of groundwater resources [4][5][6][7].This study mainly focuses on Lahore city, the second-largest urban hub of Pakistan. The city area is facing two severe problems, one is the rapid decline in groundwater level due to extensive extraction of groundwater and the other is regular flooding in the city area during monsoon season. Its expansion over time is owed to several vectors of growth, for exam...

Making Rainwater Harvesting a Key Solution for Water Management: The Universality of the Kilimanjaro Concept

“…Appropriate temporary storage before subsequent infiltration is critical to avoid contamination of rainwater. The storage capacity does not only depend on direct uses in households nor on the irregularity of rainfall, but on the target amount of water to be harvested for immediate direct use and infiltration into groundwater systems for subsequent use during the dry season [28,30]. This approach would be an apparent attempt to realize an old vision of King Parakramabahu of Sri Lanka (12th century), who stated that, "Let no drop of water flow to the sea unused by man" [4].…”

“…In the East African Rift Valley and Kenya in particular, RWH is mainly used for drinking water and agricultural needs [23,38]. It has been recognized that RWH reduces stormwater runoff, decreases watershed pollution, and improves water management in an affordable manner [23,28,30,[38][39][40][41][42]. Harvested rainwater is currently utilized for: (i) drinking water supply, (ii) domestic non-potable uses such as toilet flushing and clothes washing, and (iii) landscape irrigation and agricultural crop irrigation [43,44].…”

“…First, in cases where the risk of contamination by geogenic and anthropogenic pollutants is minimal, the harvested rainwater can be stored in natural aquifers, which will act as de facto groundwater storage systems for drinking water provision. Such systems will be analogous to artificial groundwater recharge, which is meant to replenish groundwater resources [28]. Second, contaminated stormwater can be passed through natural aquifers to achieve partial removal of contaminants in stormwater.…”

“…Technical advances during the past two centuries coupled with recent research for improved access to safe drinking water in low-income communities (decentralized systems) and efforts to rapidly transport urban runoff away from cities to prevent flooding suggest that harvested RW has the potential to provide the highest drinking water quality to a larger population [12,[23][24][25]. Moreover, in addition to using it as a direct source of drinking water, the harvested rainwater can be locally infiltrating into the sub-surface in the form of artificial recharge to increase groundwater storage in aquifers [7,[26][27][28]. Locally infiltrating rainwater prevents salt intrusion in coastal areas, and deeper groundwater drawdown and depletion, which are the most widely reported adverse impacts of excessive groundwater abstraction [9,28,29].…”

“…Moreover, in addition to using it as a direct source of drinking water, the harvested rainwater can be locally infiltrating into the sub-surface in the form of artificial recharge to increase groundwater storage in aquifers [7,[26][27][28]. Locally infiltrating rainwater prevents salt intrusion in coastal areas, and deeper groundwater drawdown and depletion, which are the most widely reported adverse impacts of excessive groundwater abstraction [9,28,29]. Additionally, compared to surface runoff in rivers and streams, locally infiltrated rainwater is less likely to come in contact with agriculture and industry-related pollution, mainly where agricultural and industrial wastewaters are not treated before discharge into the environment [30][31][32][33].…”