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Storm Water Drain (SWD) Muck / Mud Traps
Written By psaram42 - 13 October, 2009
Bangalore Roads Analysis Maintenance sewerage Others Everything else
“In most countries, sieve/meshes only hold back items which are too big to clog the drains. It is hard to stop mud from entering drains using meshes.” - IDS
IMHO
It may not be harder than clearing huge amount of mud collected over the years in these SWD. What is required is a small civil engineering design exercise, to obtain a solution to the above challenging problem. I accept that to brush aside something because of a small apparent problem is a human tendency.
However I also believe that necessity is the mother of invention.
It was JDS Chief Minister HD Kumarswamy who spear headed the much talked about BTRAC roads, at the time of execution. The covered ducts leading the storm water from the BTRAC roads to the road side SWD do have muck traps.
True Mesh / Sieve idea may not work when it comes to dealing with mud being washed away by storm water from the roads.
It has to be trapped by providing deep receptacle in each road side duct. The mud is supposed to be trapped by this receptacle which is nothing but a deeper rectangular hole in the duct. Trapping this mud at the entry level is the key to the solution. [Another example is our ordinary commode with U shape exit trap]
Some of the important points however are
1. These traps are covered. Hence it is not possible to know when the traps are full.
2. So, there should be a maintenance schedule for periodic cleaning of the traps.
3. When the design is not perfect / satisfactory there should be a continuous review and parallel research.
4. The will to find better solutions is the key.
5. We need to think ab initio avoiding the trap / awe of what is there abroad.
High time we should move ahead of what is there in developed countries.
If sieves meshes cannot do the job, think of the alternative:-
- Trap the mud at each duct feeding the main SWD
- Periodically clean the duct traps.
- It is foolish to clean the big SWD on a yearly cycle as it is the practice now.
It is only unfortunate that people in power may not be too enthusiastic about problem solving.
Are the problems themselves important in their survival?
COMMENTS
RKCHARI - 14 October, 2009 - 12:22
Sir,
Large diameter RCC Pipes instead of open drains would not solve the problem as:
a) Storm water would not be able to enter the pipes from the gutters on the shoulders and if you make holes on the pipes, they will end up being open drains once again;
b) Storm water will still require to be carried from one place to another which is absolutely unnecessary;
c) Storm water cannot be re-used for even watering plants on verge and sides.
Just my two penny worth.
Regards,
RKCHARI - 16 October, 2009 - 08:32
Dear IDS,
I think this is a brilliant suggestion and requires wide publicity through media. All Property Developers should be given strict rules to follow this idea of keeping building debris in Dumpsters.
Regards,
Chari
RKCHARI - 13 October, 2009 - 05:10
Dear PSA Saar,
Ah, but you missed the most important aspect of it being "high time we should move ahead of what is there in developed countries" !
Could you add a 4th point about seeking an entirely different solution of covered SW drains or rather point of source infiltration systems?
There really is no need for trapping the mud at each duct feeding the main SWD or periodically cleaning the duct traps or cleaning the larger SWD annually. In one fell sweep all these festering problems can be solved by getting rid of open drains altogether!
I am amazed that the authorities who occupy the decision making chairs in BBMP / BWSSB are wondering whether it is worth taking a stand on implementing closed infiltration systems in place of open drains. Where is the question of any doubt? Closed infiltration systems are working without a hitch in over 200,000 kilometres where we have intervened in 30 countries worldwide.
Is mother earth different in its basic properties of being able to infiltrate water (albeit at different speeds of infiltration depending on nature of soil) or is rainwater more viscose in India than in Western countries?
The doubting Thomases in a desparate bid to thwart anything new then turn to infiltration systems being more expensive. But have they done any cost benefit analysis? Does it not make sense to spend on a solution now and rest in peace for 50 years or more instead of paying petty amounts over any number of years and facing the continued wrath of public? And if the solution is being offered on turnkey basis and to boot on BOOT basis(pun intended), why do the authorities wish to behave like ostriches?
I wonder when Namma Bengaluru will think out of the box and take some really drastic steps "for better or for worse till the next elections do them part"!
Regards,
Chari
Naveen - 13 October, 2009 - 06:17
Mr.Ananthram,
Your assumption that a weir arrangement (similar to traps in toilets) would successfully trap all mud is incorrect. Only heavier particles in the mud will sink & get trapped, whilst most of it will emulsify & flow with water & remain at the bottoms of SWDs when water evaporates even if such deeper traps are provided. The traps will only help in minimizing accumulation of all mud in SWDs, at best. Thus, the problem will remain, but to a somewhat reduced extent with the deeper entry points.
Mr,Chari,
I am beginning to see the benefits of the system that you demonstrated & spoke of. However, until we are sure that our streets are not going to be tampered with (for laying all kinds of pipes, cables, etc.), I don't think we should take it up. When we are more or less certain that infrastructure such as drainage, water /electricity /telephone /OFC cabling are complete & that no more road widening is anticipated, we could try the system.
Why I say this is because there is still a lot of "fire-fighting" that remains to be done. When compared with other developing cities, we are still to address more pressing issues such as improvement in PTs, reduction of traffic, elimination of autos, 2-wheelers, good pedestrian infrastructure, etc. If we start laying plastic crates below ground, they will be uprooted several times repeatedly when various works are undertaken, & result in wastefullness.
Some streets in CBDs can however be tested with the system to check suitability.
BBMP and BWSSB are two separate bodies
sanjayv - 14 October, 2009 - 08:58
PSA sir,
BBMP is responsible for storm water drains, BWSSB for sewage lines and treatment. BBMP does not come under BWSSB or vice versa. Only difference is that once elections happen, BBMP will be run by an elected body answerable to Bangalore's citizens. BWSSB is run by the state, answerable to the people of the state through legislators.
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