Nature$-$based solutions $($NBS$)$ are innovative approaches that harness the power of nature to address societal challenges, such as climate change, biodiversity loss, and urbanization. Investigate the theoretical foundations of nature$-$based solutions, including principles such as ecosystem services, biodiversity conservation, and green infrastructure. How do planners and policymakers apply theoretical models of nature$-$based solutions to design and implement projects, such as urban parks, green roofs, and restored wetlands, that provide multiple benefits, such as flood protection, carbon sequestration, and recreational opportunities?