Nicola Moore applied for £7,000 from the Cumbria Community Foundation after her rented Workington property was hit.
But the 33-year-old claimed for items belonging to her landlord and lodged a second application for a property she had already received a payout for.
She was sentenced after a trial at Carlisle Crown Court.
Moore had denied making the two bogus applications but a jury unanimously found the mother-of-two guilty of two counts of fraud.
The court heard she was awarded £1,250 following her initial application, but was later asked to repay £750 in respect of items which her landlord had also claimed for.
Moore, of Windsor Road, Workington, was remanded in custody by Judge Peter Davies following her conviction on Tuesday.
Noting the "marked impact" of three nights in prison, he imposed an 18-month prison term suspended for two years and a 250-hour community service order.
She must also pay £350 in compensation to the foundation.
Judge Davies described the offences as "serious" and told Moore: "While other members of the community helped during the floods, you helped yourself."
Storm Desmond wreaked havoc across Cumbria in early December as a record month's worth of rain fell in just one day.
A woman who defrauded a charity which handed out grants to victims of last year's Storm Desmond floods has been given a suspended jail term.