Simplify the following text for a Grade 9 native English-speaking person.
Original: On 15 March 2008 , the former Councils of Noosa Shire , Maroochy Shire and Caloundra City amalgamated to form the Sunshine Coast Regional Council .
Simplified: On 15th March 2008 , the former Councils of Noosa Shire , Maroochy Shire and Caloundra City combined to form the Sunshine Coast Regional Council .