$123$#$.$

Illustrate the fundamental principles and methodologies involved in the design and analysis of sustainable urban drainage systems $($SUDS$)$ within civil engineering. Specifically, discuss the hydrological, environmental, and structural considerations that must be addressed when planning such systems, including how to effectively integrate green infrastructure, the role of permeable surfaces, and the importance of stormwater management to mitigate urban flooding. Additionally, evaluate the challenges and potential benefits associated with the implementation of SUDS in densely populated urban areas, and how these systems can be designed to not only manage stormwater effectively but also enhance urban green spaces and biodiversity. Include a discussion on the interdisciplinary collaboration required among civil engineers, urban planners, environmental scientists, and landscape architects to ensure the successful development and integration of SUDS into existing urban environments.