<p>The Khettarat, an ancestral irrigation system developed in Moroccan oases, exemplifies an ingenious approach to water management, especially in arid and hyper-arid regions such as the Drâa-Tafilalet region in southeast Morocco. Today, these systems are gradually disappearing despite significant efforts by the Moroccan government, international and bilateral cooperation, and civil society to protect and preserve them. This decline is linked to socio-cultural changes, structural drought, climate change, loss of traditional knowledge, poor governance, and the adoption of modern water extraction methods. This work explores the Khettarat system through the Water-Energy-Agriculture-Ecosystem Nexus approach, highlighting its historical and current functions. These ancestral systems depend on responsible and sustainable management of underground resources, enabling local communities to develop resilient family farming practices. In doing so, they help ensure food security, maintain ecosystem balance, and provide vital services to local populations. The Khettarat systems are therefore exemplary models of local adaptation to dry climates and climate change impacts. We also examine the main threats and challenges facing Khettarat systems today, including desertification caused mainly by siltation and silt buildup, impacts of climate change, the concerning decline in groundwater levels, and the gradual loss of traditional knowledge. Additionally, rising urbanization, rural exodus - particularly among young people - and the increasing use of deep wells upstream of the Khettarat systems, often equipped with solar-powered pumps, present significant challenges. In response, our goal is to study the Khettarat system using a systemic approach inspired by the Water-Energy-Agriculture-Ecosystem Nexus to improve the resilience and sustainability of these heritage systems.</p>