Cost sharing for the maintenance of drainage outlet systems for agricultural land will be limited to the control of vegetation and removal of channel obstructions as follows: Control of vegetation will be limited to control of herbaceous growth or removal of shrubs or small trees which do not exceed 4 inches in diameter at breast height. Movement of earth will be limited to: Cleaning of sediment traps or construction of sediment traps as is considered necessary by the soil conservation district. Removal of material which does not change the original design of the channel, or constitute a major channel reconstruction or realignment. The original design shall be maintained and removal of material may not exceed 6 inches below the original design grade of the channel. Placement of soil shall be as specified by the soil conservation district. The Secretary may provide funds for use in each county based on the mileage of ditches in each county applied for by associations and approved by districts as compared to the total mileage applied for in the State. Associations which have received funds in prior years will receive a lower priority for cost sharing purposes than those which have not. A higher priority may be given where other funds, above the required 50 percent, are available from other sources such as county cost sharing funds. In establishing priorities for the purpose of cost sharing for drainage outlet systems, the Secretary may consider other criteria which will promote the control of vegetation, the removal of channel obstructions, and debris from drainage outlet systems for the draining of agricultural land. The Secretary may provide funds through a soil conservation district. Funds are allocated for use within 12 months of the date made available to the association. The association will verify to the Secretary the expenditure of State funds and the amount of local matching funds. Work for which funds are provided shall be verified by the soil conservation district for compliance with the district approved operations and maintenance plan. Any change from the plan must be approved by the soil conservation district.