Police at the William Tyrrell dig site have drained the creek after installing a pump to reduce the water level and expose areas to fossick through for evidence of the missing toddler. Hydrologist Professor Jon Olley, who found murdered Queensland schoolboy Daniel Morcombe's remains in 2011, spent most of Thursday working around the now-cleared creek area. Police will be searching through mud for remains to be examined by the professor. Rural Fire Service officers yesterday finished removing tonnes of undergrowth and thinned trees around the creek bed edges ahead of 'doing the creek bed' today. Just before operations began today, a team of 50 police, RFS and ambulance officers, as well as civilian personnel and scientists posed for a group photo on the site and cheered. They then donned gum boots to walk into the muddy creek bottom. An electrical pump emptied the waterway from a creek near the Kendall property where William Tyrrell went missing overnight on Thursday and the area is now clear for expert work to begin Hydrologist Professor Jon Olley (centre), who found murdered Queensland schoolboy Daniel Morcombe's remains in 2011, spent most of Thursday working around the now-cleared creek area NSW Police spent hours yesterday meticulously combing the dirt of cleared bushland in Kendall, NSW for clues in the disappearance of toddler William Tyrrell in 201 An electrical pump emptied the waterway from the creek overnight on Thursday and the area is now clear for Professor Olley to commence work. It is one of three areas in Kendall, including the house from which William disappeared in 2014, being searched by Strike Force Rosann. The dig site through which the now-drained creek runs is about the size of two city terrace house blocks and is joined by fire trails with the backs of the houses along the street where William vanished. A few minutes before 9am, Professor Olley was called over to the edge of a pool of stagnant water which runs through a culvert underneath Batar Creek Road and feeds into the newly-drained creek. RFS officers notified police they had found an item - which looks like a piece of cloth or dark plastic - which had washed up onto the side of the stagnant pool. Professor Olley then inspected the piece, with police media telling Daily Mail Australia a few minutes later: 'They found something but it's nothing'. Fire officers are now working with chainsaws clearing a patch 100m up the road from where the creek search is taking place. In 2011, Professor Olley spent two months at a site near the Glasshouse Mountains recovering three bones and two shoes belonging to Daniel Morcombe, who had been murdered in 2003. At that site, which has been subjected to two major floods since the schoolboy's remains had been discarded there, 500 cubic metres of sand was removed. After the area was reduced by a metre to the same level, Professor Olley found 'undulations' in a surface under which he made the discovery of the boy's remains. Professor Olley told Daily Mail Australia that the Tyrrell search site was 'more complex' partly because it was over a larger area. He said that items of interest may have been washed up on neighbouring properties to the site. The search for the remains of missing three-year-old William Tyrrell is entering its fifth day on the NSW mid north coast, as rain threatens to hamper search efforts. Showers and possible thunderstorms are forecast for the mid north coast on Friday. The carefully preserved scene at a patch of bushland near to William Tyrrell's foster grandmother's house in Kendall, where the three-year-old was last seen On Thursday, Australian Federal Police officers brought in ground penetrating radar to scan a concrete slab at the Kendall property that belonged to the boy's foster grandmother. William disappeared from the property seven years ago, but the slab was laid after that. Nothing, however, was detected under the slab. It comes after police investigated theories he may have fallen from a balcony at the property. Earlier this week police also seized a Mazda that previously belonged to the foster grandmother, who has since died. Cadaver dogs have also been on the scene. One of the last known pictures taken of William Tyrrell on the day he disappeared from his foster grandmother's house at Kendall on the mid north coast of NSW An ongoing search in an area of bush near the Kendall home is continuing, having sparked excitement on Wednesday afternoon as police examined an item that turned out to be unrelated. That same day police also charged the boy's former foster parents over an unrelated alleged assault on a different child. The pair are due to face court at Hornsby on Tuesday Prime Minister Scott Morrison praised investigating police officers on Thursday, saying they have made 'huge inroads' and would 'never stop' looking into the mysterious disappearance. All rights reserved for this news site (dailymail) and under his responsibility