UQDGYUTSD7

1. TECHNOLOGICAL UNIVERSITY(YAMETHIN)
DEPARTMENT OF CIVIL ENGINEERING

2. RAINWATER HARVESTING SYSTEM

3. Introduction
Rainwater harvesting is defined as a method for
-Collection of rainwater
-Flow system from source to storage
-Designing the storage tank
-Testing parameter of collected water according to NEQG
-Applying required treatment for domestic water use

4. Scope of the study
-Study area at 4storyed building
-Apply National Environmental Quality Guideline

5. Aim and Objectives
-To design rainwater harvesting for 4 storyed building
-To reduce underground water usage
-To avoid flooding of road
-To use adequate water demand

6. Uses of rainwater
• Recharge underground water
• Gardening
• Livestock
• for Irrigation purpose

7. Advantages
• Technologies are simple to install and operate
• Easily trained to implement
• Construction material are readily available
• Running costs are almost negligible
• Water collected from roof catchment is acceptable for domestic
purposes

8. Component of roof top rainwater harvesting
system
• Catchment area
• Delivery system
• Storage system
• Filtration system

9. System performance model

10. Runoff Estimation
ER=R.A.C
ER=effective runoff(m3)
R=rainfall(mm)
A=catchment area(m2)
C=runoff coefficient(roof inclined 0.85-0.95)

11. The changes of storage tank volume
Vt = Vt-1 + Qt – Dt – Et – Lt
Vt=storage volume at time t(m3)
Vt-1=storage volume at time t-1(m3)
Qt=water requirement release in lapse of time(m3)
Et=Evaporation(m3)
Lt=losses(m3)

12. CALCULATIONS FOR NUMBER OF RAINWATER PIPES(R.W.P.)
n=Q / (0.785d2 ×v)
n=number of pipes
Q=discharge calculated
d=diameter of pipe
V=velocity of water on the roof

13. Expected outcomes
-Decreased demand
-Reduce runoff
-Improve underground recharge

14. References
1) A Dual-Mode System For Harnessing Roof water For Non-Potable
Use
2)Environmental Analysis of Rainwater Infrastructures in Diffuse and
Compact Urban Models in Mediterranean Climate
3) The Sizing of Rainwater Stores Using Behavioural Models
4) Modelling the performance of rainwater collection systems: towards
a generalised approach
5)Handbook of Water Harvesting

15. THANK YOU