It will also look at the continued running costs of the fountain and whether officials properly took into account Diana's popularity when it was being constructed.
'It will also look at whether officials properly took into account Diana's popularity in the planning stage and the cost of its construction.'
The granite moat, designed by Kathryn Gustafson and built by Geoffrey Osborne cost £3.6 million, with more money being spent on repair work immediately after it opened.
The Queen officially opened it in July last year - a year later than planned - but it was instantly plagued with problems. It became blocked by fallen leaves, suffered a broken pump and had to be closed after two weeks when visitors slipped while paddling.
A memo from Will Weston, chief executive of the Royal Parks Agency,
revealed there were 900 'incidents' in the first fortnight, including 15 cases of personal injury. It reopened in August last year but with new rules banning people from paddling.
The Royal Parks then decided further repairs were needed when the area around the fountain turned into a mud-bath. More than 5,000 people an hour visited the tourist attraction in the summer and the waterlogged grounds could not cope.
It was closed again in January for alterations to the ground around the fountain, reopening at the beginning of May.