Added data object and factory for sediment load calculation. The factory provides two methods to get sediment load data: The first is to get an array of loads for a specific range at a river, these loads contain the time and description. The second is to get a single sediment load with time, description and data values.

select.abflusstafel = SELECT ABFLUSSTAFEL_NR, \
                             ABFLUSSTAFEL_BEZ, \
                             GUELTIG_VON, \
                             GUELTIG_BIS, \
                             PEGELNULLPUNKT FROM ABFLUSSTAFEL WHERE MESSSTELLE_NR LIKE :number