1. Managing water and drainage for sugarcane production, in the Herbert region.

2. Why do we need drainage in the Herbert
Sustained periods of wet weather are common
Cane area is generally flat with little fall
Natural drainage is away from river – long way to an outlet
Many soils are heavy textured with slow permeability
Flooding and widespread waterlogging are common, particularly Jan-April
Generally best yields occur after a succession of dry years
Herbert annual rainfall & cane yields

3. Flooding and inundation
Flooding and inundation both involve submergence of soil surface (and sometimes cane crop) by water
Flooding – short duration with flowing water coming from off-farm (rivers) caused by high rainfall
Lodged cane
Scouring/erosion
Silt & debris on leaves/growing point
Inundation involves standing or slow flow water over low lying areas. Can remain for weeks or months
impacts more widespread and serious
waterlogging, saturated soils, low soil oxygen
denitrification and toxic gases (ethylene) from anaerobic breakdown of OM and trash blanket

4. Yield losses from waterlogging & high water tables
Waterlogging results from saturated soil. Soil pores filled with water. Roots and soil organisms unable to access oxygen
Research conducted by BSES and CSR estimated yield losses caused by high water tables
3 separate studies concluded that cane yields reduced by 0.5 t cane/ha each day water table < 0.5m from soil surface
Relationship between cane yield and water table height
(Rudd and Chardon 1977)

5. Laser levelling and surface drainage
Widely used by cane growers to improve surface drainage and reduce inundation
Blocks surveyed using laser technology & GPS
Optimum design based on survey data to minimise soil movement
Laser guided levelling with GPS to cut and fill

6. Headland drainage Headlands often higher than field level
Barrier to surface and sub-surface water flow
Headland lowering should be part of laser levelling
Inter-rows should drain onto lowered headlands
Lowered headland could be a flat bottomed spoon drain

7. Farming low-lying, poorly drained heavy clay soils
Mound planting widely used to raise plants above mean level of field
Improves yield of cane and fallow crops
Use of soil conditioners (such as mill ash & river sand) improve internal drainage
Mole drains and slotted pipes can help lower water table
GGIP project – Vince Russo

8. Integrated drainage management
Surface drainage work in different blocks needs to be integrated into a farm drainage system
All blocks in a sub-catchment should be surveyed and laser levelled together
Drainage then needs to be integrated across farm boundaries
Best done as a drainage board

9. The Lower Herbert Water Management Authority
Amalgamation of drainage boards formed in mid 1970s (Mandam, Ripple Creek, Forresthome, Loder Creek, Seymour, Ti Tree, Perry’s drain)
Gazetted November 2005
Includes SIIP works worth >$4M (pumps, smart gate, overflow channel, wetlands & retention areas)
203 rate-payer landholders over 14,800ha
115km of board drains connected to farm drains
900 crossings (culverts, inverts, pipes)
Management of urban outflows from Ingham
Efficient removal of agricultural & urban drainage through a co-ordinated network of drains

10. Lower Herbert Water Management Authority
Ingham

11. Network of drains within Authority

12. Crossings within Authority

13. Urban drainage area within Authority

14. Mandam pumps from SIIP

15. Ripple Creek by-pass channel from SIIP

16. Ripple Creek smartgate and wetlands