Where can i find texas state stutes on Drainage of surfaec water?

i purcheset 4 ackers Galveston county texas, there is a drainage dich that runs thrue my property,in the years past the county has routed 4 miles of residential drinage in to the dich,and now the dich is grossly in adequate to handle all the run off from the above area,and floods my prop-the county will maintaine it, be couse in the years past it was specfied a closed right of way,privat propty,and on the county plot plane it specfyed it is the respirability to maintain by the property owners.how can i get this changed,HELP I AM DROWNDING