LV EN RU DE FR

Water Management: Land Drainage and Irrigation

Course developer

Course abstract

In this course the following are presented: tasks, functions and methods of land drainage and irrigation to remove excess soil water providing necessary conditions for intensive farming. Course provides advanced knowledge on the drainage planning, parameters and their calculation methods, design of drainage and irrigation structures, construction works, materials. Tasks and the necessary measures during the implementation of land reclamation works are discussed.

Learning outcomes and their assessment

• The course develops knowledge and understanding on the soil water balance and how to develop suitable conditions for crops depending on agricultural practice and technology. Exam.
• The course enables students with an ability to evaluate soil moisture balance and use of water resources with the scope of land reclamation systems and agricultural use of land. Two tests.

• The course elaborates competence to evaluate technical conditions of land reclamation systems and structures and to find out imperfections and failures and necessity of repairment works. Five practical tasks completed and sub

Course Content(Calendar)

1. Factors affecting the soil formation, mechanical texture and division. Soil classification. Water types in soil, plant available water. Soil moisture regime. Drainage and irrigation impact on soil moisture regime and fertility. Soil conservation. Over moist soil conditions. Soil hydro-physical properties and their changes. Water balance equation, soil over moisture types and reasons. Drainage system and basic operating principles. – (2h)

2. Hydrology. River hydrology, discharge computation methods for open channels, drainage collectors and culverts. Hydraulics. Hydrodynamics, tasks within the land drainage projects. Calculations of hydraulic structure parameters, water-carrying capacity, flow velocity, depth and water levels. – (1h)

3. Land reclamation, division and measures of water and land management systems. Land drainage importance and tasks in the context of agricultural production and environmental protection. Land drainage techniques depending on the soil over moisture. Drainage schemes and components. Impact of drainage system exploitation condition on the whole system operation. – (1h)

4. Open land drainage systems – channels. Operating principles and parameters of the channels, application depending on land use type. The advantages and disadvantages of channels from the land drainage and management perspective. – (1h)

5. Subsurface drainage systems – tile drainage. Tile drain, drainage system as the essential drainage measure in the intensive agricultural areas. Subdivision of drainage, materials, parameters. Auxiliary structures for the drainage – outlets, control wells, surface water inlets, filters, their tasks in the drainage system. Evaluation of land drainage – the advantages and disadvantages from the land drainage and management perspective. Environmentally friendly drainage systems. Sedimentation basins, constructed wetlands, channel meandering, boulder piles in the channel bed, controlled drainage etc. – (1h)

6. Unsatisfactory water regime for the drained soil, subsurface drainage damages. Indication methods of possible damages and prevention measures. Reasons of surface water accumulation, its prevention. Formation of soil water erosion, consequences and mitigation measures. Insufficient land drainage effectiveness, reasons, identification and prevention. Impact of drainage network technical condition on drainage system operational effectivity. – (1h)

1st Test (about 1 – 6 lecture topics)

7. Irrigation. Water balance, moisture deficiency. Irrigation types and methods. Surface irrigation. Furrow irrigation. Watering/sprinkling. Drip irrigation. Subsoil wetting. Irrigation methods used worldwide. – (1h)

8. Soil active layer water balance. Evapotranspiration. Irrigation regime. Soil moisture volume changes. Graphic-analytic design of the irrigation regime. Irrigation norm m3/ha. Suggested irrigation doses. – (1h)

9. Watering. Irrigation system, equipment. Irrigation nozzles: deflector, centrifugal, jet. Rotating irrigation machines. Placement schematics for the irrigation machines and nozzles, operation, malfunctioning, watering quality. – (2h)

10. Mobile irrigation equipment. Equipment fittings and sets of equipment. Stationary watering systems. Long distance positional operation irrigation equipment. Multi-supporting front-mounted pipelines. Band irrigators. Radial irrigation equipment. – (1h)

11. Drip irrigation. Drip irrigation system. Construction and division of drippers. The advantages and disadvantages of drip irrigation. Soil subsurface wetting. Bilateral drainage systems. Requirements for the installation of bilateral drainage systems. Structure of two-way drainage systems. Advantages and disadvantages of wetting the subsoil. – (1h)

12. Water supply network. Self-priming and pressure line supply network. Mobile and covered irrigation pressure pipelines. Hydraulic calculation of water supply network, pipelines. Water sources - watercourses, water bodies, their suitability for irrigation, salt content, bacteriological pollution. Pumps. Mobile pumping stations. Operation and maintenance of irrigation pumping stations, pressure pipelines and irrigation equipment. – (1h)

13. Usage, caring and maintenance of drainage systems. Ownership of drainage systems and responsibility for their operational status. Requirements of Laws and Regulations: Land Reclamation Law, Operation and Maintenance Rules for Land Reclamation Systems, LBN 224-15, ZMNI Industry Standards. – (1h)

14. Composition of maintenance, maintenance works, execution times. System defects, their detection principles, explanation of the cause, prevention. – (1h)

2nd Test (about 7 – 14 lecture topics)

Topics for practical works:
1. Reading of the topography and drainage project plans (3h)
2. Planning of renewal or new drainage systems consisting of open waterbodies (3 h)
3. Hydrological and hydraulic calculations of diches (3h)
4. Calculation of distance between subsurface drains (3h)

5. Solutions of rebuilding of subsurface drainage system (4h)

Requirements for awarding credit points

1. Written exam:
• questions about theoretical course;
• tasks based on questions similar to practical works that was carried out during the semester. Solution can be gained through calculations or graphically achieved.
2. Two tests completed successfully.

3. Five practical works are carried out.

Description of the organization and tasks of students’ independent work

1. Every student must be prepared for two tests independently. In the tests there will be included question based on the topics of lectures.
2. Practical works will be worked out in the auditorium. Descriptive part and graphical design should be done in accordance with task, guidelines for student works and lecturers directions during practical work.

3. For the exam student should prepare independently.

Criteria for Evaluating Learning Outcomes

1. General rules. The results of exam will be assessed according to sum of points earned in written exam, tests during the semester as well as points earned in practical works will be added. 100 points can be potentially earned in total, that corresponds to the mark of 10.
2. Tasks to be done:
2.1. two tests where it is possible to earn 10 points in each of tests (20 points in total);
2.2. five practical works where it is possible to earn 5 points in each of practical works (25 points in total);
2.3. written exam where it is possible to earn 20 points in the part of theoretical questions while practical tasks provide the possibility to earn 35 points (55 points in total).
3. The assessment of total rating. The learning outcomes of the student will be rated in the conditions when in each of tests, practical works and in written exam will be earned not less than 50% of the potential amount of points was possible to earn. However, exception is allowed according to procedure explained in section 3.2..
3.1. The final mark of the overall student achievements will be rated according to total amount of points earned by carrying out the works described in section 2. as well as the conditions described in sections of 1 and 3. will be considered in the assessment:
• mark 3 if less than 50 % of points will be earned in written exam;
• mark 4 if 50...54 points earned;
• mark 5 if 55...60 points earned;
• mark 6 if 60...69 points earned;
• mark 7 if 70...79 points earned;
• mark 8 if 80...89 points earned;
• mark 9 if 90...95 points earned;
• mark 10 if 95...100 points earned.
3.2. If student was able to earn not less than 36 points within the tests and practical works during the semester, then it is allowed for the student to skip the written exam. In that conditions the outcomes of student will be rated as follows:
• mark 8 if 36…39 points earned;
• mark 9 if 40…42 points earned;

• mark 10 if 43…45 points earned.

Compulsory reading

1. E.Farr and W.C.Henderson. Land drainage. London and New York, 1986. 251 lpp. Nav liel. b-kās
2. Ritzema H. P.(editor–in-Chief). Drainage principles and Applications International Institute for Land Reclamation and Improvement. Netherlands: ILRI. Wageningen, the Netherlands, 1994. 1125 p. Nav liel. b-kās
3. Ritzema H.P., Kselik R.A.L., Chanduvi F. Drainage of irrigated lands. FAO of the United Nations. Rome: FAO, 1996. 74 p. Ir LLU FB 1 eks.
4. Snellen W.B. Irrigation scheme operation and maintenance. FAO of the United Nations. Rome: FAO, 1996. 48 p. Ir LLU FB 1 eks.

5. Brooks K.N., Ffolliott P.F., Magner J.A. Hydrology and the Management of Watersheds. Ames, Iowa: John Wiley & Sons, 2013. 533 p. Nav liel. b-kās

Further reading

1. Shaw E.M. et al. Hydrology in practice. London; New York: Spon, 2011. 543 p. Ir LLU FB 1 eks.

Periodicals and other sources

1. Agro Tops. Zinātniski praktisks žurnāls zinātniekiem, agronomiem, zemniekiem. www.agrotops.lv/. ISSN 1417-5164

2. World Water and Environmental Engineering. Surrey: Faversham House Group Limited. Journals ISSN 1354-313X.

Notes

The course is dedicated for the study programme Sustainable Agriculture