Thalle worked with the NYCDEP on a preparatory project at Gilboa Dam, conducting large-scale site development, adding a construction bridge, building site access and haul roads, and grading staging areas for vehicles and equipment.

Scope of work included:
Clearing and grubbing of the site including the removal of trees.
Site construction roads, guiderail, temporary stream crossings, access gates, vehicle/equipment staging areas, and soils stockpiling area. Grading and paving of roads and staging areas.
Installation of permanent site access roads. Furnishing and installing environmental controls, temporary site fencing and gates; temporary water, sanitary, lighting, power, and stormwater utilities; a temporary bridge; water supply wells; development and implementation of a stormwater pollution prevention plans; operation and maintenance of existing siphons for the duration of the contract to facilitate the installation of the crest gates; furnishing and installing  dust, soil erosion and sedimentation control features.

The Gilboa Dam Preparatory Project was completed in July of 2011.