Typically, bund walls are built from brick or block, but for large liquid volumes, reinforced concrete may also be used. For detailed construction info on bunds ranging from 1000 to 25000 litres, refer to CIRIA Report R163 'Construction of bunds for oil storage tanks'.
There is more than one author by this name in the Goodreads data base. For the author of Gretchen's (Mis)Adventures, see https://www.goodreads.com/author/show...