Hydraulic Analysis
The following has been extracted from the notes of my training course ‘hydraulics and irrigation for on-site wastewater management’, conducted by the Centre for Environmental Training:
On-site system performance is dependent on both the treatment system and the land application system. Poor performance or failure is common in one or both elements of on-site systems. Poor hydraulic design is often a factor…there is little evidence of good hydraulic design in older systems and only limited evidence in many newer systems. Poor hydraulic design is evident in:
- local overloading
- uneven distribution
- poor matching of dosing volume to size of irrigation area
- line and emitter spacing often poorly matched to requirements of soil and vegetation
- head loss
- inadequate pressure at emitters
- irrigation area too large to load evenly and effectively.
Where hydraulics is important:
- tank sizing
- treatment system component sizing
- manifold sizing and design
- pump sizing
- correct selection and matching of componentry
- land application system sizing.
Sound hydraulic design:
- ensures treatment system and land application elements are matched
- provides a higher level of assurance that long term performance is maintained
- ensures regulatory requirements are met, even if not recognized or demanded by regulatory agencies
- should be mandatory.
Hydraulic design has significant bearing on performance for a modest extra cost.
