Sustainable drainage systems (SuDS) for rainwater harvesting and stormwater management in temporary humanitarian settlements

Kiran Tota-Maharaj, Oluwatoyin Opeyemi Ajibade, Shanika Arachchi, Colin Douglas Hills, Upaka Rathnayake, Sustainable drainage systems (SuDS) for rainwater harvesting and stormwater management in temporary humanitarian settlements, Nature-Based Solutions, Volume 7, 2025, 100227, ISSN 2772-4115,
https://doi.org/10.1016/j.nbsj.2025.100227. 

Rainwater Harvesting (RWH) is described as the interception and collection of rainwater and stormwater runoff for use.  Implementing RWH systems across Temporary Humanitarian Settlements (THS), such as refugees and internally displaced people (IDPs) camps, can improve the quantity and quality of available water resources, minimise stormwater runoff volumes and reduce the costs of providing water. Other benefits of implementing RWH systems across THS include a reduction in volume of attenuation storage required to prevent flooding and the delivery of sustainability and climate resilience across the settlements

Abstract: Effective management of stormwater runoff is crucial in refugee camps and temporary shelters. Across the Africa, this is vital especially with the intense rainfalls due to the climate effect. Sustainable Drainage Systems (SuDS) can be implemented to provide potential sources of water resources across refugee camps and internally displaced people (IDPs). The performance of two SuDS (engineered wetlands and biofilters) was evaluated to assess their effectiveness at reducing levels of pollutants in harvested rainwater and stormwater under simulated environmental conditions of an IDP camp. The SuDS comprised a matrix of sub-surface bedding materials and filter media. Stormwater quality analysis aligned with the WHO and CIRIA standards was carried out over 61 weeks simulating environmental conditions. The SuDS significantly reduced nutrients and organics loading from the influent stormwater. The Constructed Stormwater Treatment System S1-a had an overall high performance in removing impurities (BOD – 60 %, COD – 70 %, Turbidity – 70 %, Colour – 72 %, Phosphates – 63 %, Ammonium – 57 % and Nitrates – 57 %). In addition, the Refugee Camp Engineered Stormwater Treatment System S2-d has overall well-performed impurities removal (TDS – 52 %, COD – 100 %, Turbidity – 100 %, Colour – 41 %, Phosphates – 96 %, Ammonium – 98 % and Nitrates – 88 %). The outflow samples from these SuDS found the concentrations are with high standards. However, it is recommended that the treated stormwater be reused for non-potable sources in these conditions. The implementations of this research findings can be further incorporated into the United Nations sustainable developmental goals of good health and wellbeing (SDG 3) clean water and sanitation (SDG 6), and Peace, justice and strong institutions (SDG 16).

Keywords: Rainwater harvesting; Stormwater management; Sustainable drainage systems; Temporary humanitarian settlements