And with lambing about to start, long detours are required to move his Blackface sheep and machinery.
Mr Mitchell knows it will take a five-figure sum to replace the bridge which spanned the Megget Water and he is unlikely to get insurance for a new structure.
"The trouble is there is a high risk similar floods will happen again," he told The Wee Paper.
Mr Mitchell, who has farmed Henderland man and boy, believes the problem is man-made, a result of the way the vast Megget Reservoir, a mile upstream and retained by the largest earth dam in Scotland, and St Mary's Loch, a mile downstream where the Yarrow Water rises, are being managed by Scottish Water.
He has already discussed his concerns with representatives of the quango.
"Because the Megget and the loch are being kept full all the time, when the November deluge arrived they simply overflowed," said Mr Mitchell. "It was like turning on the tap in an already full bath."
In fact, 3.5in of rain fell in just 27 hours between November 19 and 20 and the Yarrow Water rose to record levels as it roared towards the Ettrick Water and Selkirk.
En route, it inundated around 20 properties, including the Yarrow fish farm and the Gordon Arms Hotel, and washed away another bridge, at Ladhope near Yarrow Feus. The Riverside Nursing Home in Selkirk was evacuated although, thankfully, recent protection work on the Long Philip Burn meant the town emerged largely unscathed.
Mr Mitchell says the policy of maintaining high levels at the dam, which supplies most of Edinburgh's drinking water, and the loch have persisted since the 1990s and led to a general raising of the water table in the valley.
While accepting that Scottish Water is adhering to the letter of water legislation, he believes the answer is to lower the levels by one or two metres to accommodate heavy rainfall without overflows adding to already swollen rivers.
Councillor Vicky Davidson agrees and has called a public meeting on flooding in the Yarrow Valley. It will take place in Yarrow Feus Hall on Wednesday February 17 at 7.30pm.
In attendance will be two Scottish Water bosses: regional community manager Bill Elliot and asset planner Dougie Scott, along with David Green, Scottish Borders Council's flood-protection programme officer, and Conor Price, the council's Selkirk flood-prevention officer.
Ms Davidson said Mr Price had also had talks with Scottish Water about lower water levels to allow spare capacity in the event of a flood.
"While the company may be prepared to do this in the longer term, this is no comfort to Yarrow residents if another flood was to happen next week," she told us. "We will be looking for answers."