The purpose of this Key Features Brief is to present the important technical features and components (the Key Features) of the LESMP in sufficient detail for the LESMP to be defined and developed. The Key Features will set the design and operational parameters for the trials proposed within the LESMP, so that, when implemented, they can be conducted in a planned manner, and their outcomes measured and assessed. The results will lead to the development of ongoing measures and methods for properly maintaining the Entrance into the future.