Revaluation, depreciation and impairment

PP LLC owns and controls few land and buildings, plants and equipment. On January 1, 2001, the entity bought land and necessary buildings for 1,500,000 USD all together. The cost of individual assets had 1:2 ratio. The plants with all necessary equipment were bought for 2,750,000 on the same date. At that time, the industry professional reviewed land and buildings, and plant and equipment, estimated that they have 20 and 25 years, respectively. In order to be consistent with economic life of assets, it was decided to use straight-line method to depreciate all available assets. The entity assumed that there would be no scrap value at that time.

However, due to financial crisis occurred in the second half of 2008, the management decided to change their estimates regarding depreciation policy, and they considered to apply revaluation model in order to be consistent with market. As of January 1, 2009, they had to downgrade the value all available assets by 40% of their original cost, and because chief economist expected an economic recovery in upcoming years, they estimated that the residual value for both land and buildings and plant and equipment would be 15% of the revalued amount once the impairment was recorded. The useful lives of assets remained unchanged

In September 2013, some small tsunami-driven waves hit three cities along the east coast. Due to small damages to the building, it was difficult to price the damage, hence the management decided to review the assets at the beginning of next accounting year. The management reviewed the useful life and estimated the buildings to have another 9 years left to operate at full potential, after which will be disposed at pre-specified price.

Required:
You need to prepare a summary, pointing out the following points, for the year-end March 31, 2018:
• Annual depreciation for individual assets
• Impairment loss or revaluation surplus of assets in relevant years
• Updated residual values, useful lives and annual depreciation charges in relevant years
• Journal entries for key changes.