1. به نام خدا مهندسي زهکشي پائيز 1395

2. زهکشي سطحي -زهکشي زيرزميني زهکشي داخلي - زهکشي خارجي
زهکشي فرآيند خارج کردن آب سطحي اضافي و مديريت سفره آب زيرزميني کم عمق از طريق نگه داشت و دفع آب و مديريت کيفيت آب براي رسيدن به منافع دلخواه اقتصادي و اجتماعي است، در حالي که محيط زيست نيز حفظ شود.
زهکشي سطحي -زهکشي زيرزميني
زهکشي داخلي - زهکشي خارجي
زهکشي مانعي (حائل) - زهکشي گشايشي
زهکشي افقي - زهکشي عمودي
زهکشي مرحله اي

3. کليات زهکشی تخلیه آب و املاح اضافه (تعریف اضافه یا مازاد) در حد ضرورت
Not a drop more
جلوگیری از تجمع آب و املاح اضافه
مدیریت سطح آب زیرزمینی
مدیریت تخلیه آب و املاح (زهاب)
احیا و پایداری حاصلخیزی اراضی
هزینه ها و منافع اقتصادی زهکشی
زهکشهای فرعی (لاترال) – جمع کننده (کولکتور) – اصلی – خروجی
خروجی یا تخلیه گاه (outlet) مهمترین بخش یک سیستم زهکشی

4. طراحی زهکشی
جانمایی اجزای یک سیستم زهکشی زهکشهای فرعی جمع کننده – اصلی و خروجی
زهکش فرعی عامل اصلی زهکشی
خروجی مهمترین بخش یک سیستم زهکشی
طراحی سیستم زهکشی (اندازه لوله – عمق – فاصله – طول – شیب)
اصول کلی زهکشی :
کامل به لحاظ پوشش و ظرفیت
جریان ثقلی
پیوستگی
بهینه
پایداری (ملاحظات زیست محیطی – منابع پایین دست)

6. Cost Effectiveness Drought Prevention Fertilizer Efficiency
Good drainage promotes good root growth as crops reach for the capillary water in the soil. In a field with high water tables young plants only develop shallow root systems. When dry weather arrives shallow roots can not supply enough water to the crops. Consequently it withers and dies. Crops in well drained soils have a better root system to reach the required water.
Fertilizer Efficiency
Good drainage makes any fertilizer work better. Increased fertilizer usage is no alternative to good drainage - they must be used hand in hand. Healthier soil increases the effectiveness of fertilizers, and at today’s consistently climbing cost it is imperative that the maximum benefit is derived from every ounce supplied.
Environmental Control
Drainage reduces surface run off by increasing the water holding capacity of the soil so erosion is dramatically decreased in many cases. During heavy rain, water is removed by being absorbed into the soil and filtering down through the soil to the drain, rather than running over a saturated surface and washing away valuable soil.
Increased Quality
Good drainage contributes to quality Regardless of the field, healthy roots support healthy crops. Well drained soil discourages plant disease. Also there is a direct relationship between drainage and crop quality
Increased Profit
Increased crop yields equals increased profits.
Less Soil Damage
Good drainage avoids unnecessary soil damage such as compaction, smearing and crusting. Working in wet fields causes damage to soil structure which may take years to put right. Also, equipment which becomes bogged down means costly, time-consuming delays and often expensive damage to the machinery.
Time and Labour Savings
Good drainage eliminates the need to work around and then return to wet spots. Profitability can be increased through faster field work and a reduced need for repeat operations such as reseeding spots.
Cost Effectiveness
Expenditure of field drainage should be looked upon as a capital investment. It can bring benefits for many years.