vegetation, draining the land, and leveling uneven terrain. By the following month, chief engineer Viele reported that the project employed nearly 700 workers. Olmsted employed workers using day labor, hiring men directly without any contracts and paying them by the day. Many of the laborers were Irish immigrants or first-or-second generation Irish Americans, and some Germans and Italians; there were no black or female laborers. The workers were often underpaid, and workers would often take jobs at other construction projects to supplement their income. A pattern of seasonal hiring was established, wherein more workers would be hired and paid at higher rates during the summers. For several months, the park commissioners faced funding issues, and a dedicated workforce and funding stream was not secured until June 1858. The landscaped Upper Reservoir was the only part of the park that the commissioners were not responsible for constructing; instead, the Reservoir would be built by the Croton Aqueduct board. Work on the Reservoir started in April 1858. The first major work in Central Park involved grading the driveways and draining the land in the park's southern section. The Lake in Central Park's southwestern section was the first feature to open to the public, in December 1858, followed by the Ramble in June 1859. The same year, the New York State Legislature authorized the purchase of an additional at the northern end of Central Park, from 106th to 110th Streets. The section of Central Park south of 79th Street was mostly completed by 1860. The park commissioners reported in June 1860 that $4 million had been spent on the construction to date. As a result of the sharply rising construction costs, the commissioners eliminated or downsized several features in the Greensward Plan. Based on claims of cost mismanagement, the New York State Senate commissioned the Swiss engineer Julius Kellersberger to write a report on the park. Kellersberger's report, submitted in 1861, stated that the commission's management of the park was a "triumphant success". 1860s Olmsted often clashed with the park commissioners, notably with Chief Commissioner Green. Olmsted resigned in June 1862, and Green was appointed to Olmsted's position. Vaux resigned in 1863 because of what he saw as pressure from Green. As superintendent of the park, Green accelerated construction, though having little experience in architecture. He implemented a style of micromanagement, keeping records of the smallest transactions in an effort to reduce costs.