1                  Storm water drainage

 

1.1                                    Introduction

The average annual rainfall over Shimla is about 1650 mm.  The hilly terrain of Shimla has gifted itself with a good natural drainage pattern by the open streams or nallahs.  The rainwater runoff finds its own course to open streams or nallahs.

 

1.2                                    Institutional Responsibility

Public Works Department (PWD) is responsible for construction of side storm water drains on the either of PWD road network in Shimla City.  Cross drainage works in form of culverts and bridges on the PWD road network is also under PWD, which also is responsible for its maintenance.

The open streams or nallahs within Shimla city is under the control of Shimla Municipal Corporation.

 

1.3                                    Natural Drains

The Kufri-Dhalli-Sanjauli-Ridge-Tutu spinal is a drainage divide of Shimla city. The tributaries on southern side go to Yamuna and those on northern side to Satluj. Shimla has 13 major nallahs and number of minor nallahs, which are natural drains for rain water and off late for waste water too. Some lining is visible along these major nallahs but is not effectively coursing the storm water.  Most of the natural drains (nallahs) are encroached upon and disposal or debris is a common view of the nallah.

 

Plate 10.1 Natural Drains of Shimla

 

1.4                                    Road Side Drains

KSC road and Motor Round Road have roadside open drains on the hilly side, which functions mainly for the water draining from the rocks and small water springs. These drains are further connected to near by natural drains (nallahs). At some locations, they are provided with cross drainage works on the roads for the water to drain from the hilly side to the valley side.  Roadside drains are provided on the hillside of the municipal roads, which are basically a shyaway type of drain as shown in Plate 10.1 to Plate 10.3.  Even though storm water drains are constructed by SMC, PWD and respective SADA while upgrading roads, the maintenance of storm water drains are least attended with only response during excessive damage to the drains.

 

Plate 10.3 Encroachment of Road Side Drains in all possible ways

 

It may be not a misnomer to call these roadsides drains as utility ducts cum drains, as most of the roadside drains have become a common right of way for water pipe lines, electric cables, telecommunication cables, TV cables and a few locations as waste water sewerage disposal nodes.

 

1.5                                    Issues and Aspects

 

Ø         Choking of Nallahs due to disposal of debris and garbage into the drains

Ø         Silting of drains due to constant blockages

Ø         Dislocated and damaged old lining of the drains

Ø         Encroachment of Nallahs

Ø         Free access to dispose wastewater from nearby habitation and establishments into the natural drains

Ø         No cleaning of natural drains and no clearance of excess floral growth on the drains

Ø         Unpleasant odour of dirty water flowing in the drains

Ø         Absence of check dams to conserve rain water

Ø         Low coverage of road side drains

Ø         Irregular and insufficient roadside drains sizes causes overflow of run off water, which is very detrimental to black top roads

Ø         Poor maintenance of road side drains

Ø         Indiscriminate laying of services pipes and lines along the drains by other department and agencies

Ø         Absence of comprehensive data on storm water drainage network

 

1.6                                    Vision and Goals

Text Box: “Provision of long lasting Clean Natural and Road Side Drains”

 

 

 

 


 

DESCRIPTION

2006

2011

2016

2021

% Road side drains to length of road network

10

50

75

100

% Lining of natural drains

0

90

100

100

% Conservation of rain water by check dams

0

90

100

100

 

 


 

1.7                                    Strategy and Identification of Interventions

 

To build a robust storm water drainage network and to achieve the storm water drainage vision for Shimla City, following are strategies for Integrated Drainage Project for Shimla Planning Area:

Rehabilitation of natural drains

The Municipal Corporation has undertaken a reconnaissance survey of the natural drains and has prepared a block cost estimate for restoration, rehabilitation, training and cleaning natural drainage system.  The list of identified natural drains, which are to be taken up for renovation in the first instance, is given in Annexure 23.5 and Annexure 23.6

Removal of unauthorized structures and encroachment on natural drains

Regulatory framework for removal of unauthorized structures and encroachment of natural drains should be included under municipal acts as a policy to prevent further encroachment and usage of natural drainage for other purposes

Construction of rainwater harvesting structures

Rainwater harvesting as covered under the proposed Integrated Water Supply Project should be done to decrease water demand of Shimla

Construction of roadside drains as per drainage design

Roadside drains should be as per the design requirements with specifications to handle the run off water and to provide cross drainage works for effective draining of rainwater into natural drains

Increase in frequency of cleaning of drains to avoid silting

Frequency of cleaning of drains should be increased which will help in avoiding silting and desilting of drains and eventually improve the efficiency of the drain capacity

 


 

1.8                                    Sectoral Investment Plan

 

S.N.

Project

Total Cost (Lakhs)

2007

2008

2009

2010

2011

2012

1

Technical Studies: Master Plans and DPRs

 100

100 

-

-

-

-

-

2

Renovation of Identified Natural Drains

413.76

-

413.76

-

-

-

-

3

Renovation of Open Drains

84.50

-

84.50

-

-

-

-

4

Construction of roadside drains as per drainage design

810.00

-

810.00

-

-

-

-

 

Total

 =SUM(ABOVE) 1408.26

100.00

1308.26

-

-

-

-

 

 


 

1.9                                    Project Information Sheets

 

Project Title: Renovation of Identified Natural Drains

 

Project Description:  Renovation of 22 natural drains, which are within the corporation limits by lining of the drains, removal of debris and garbage, desilting, removal of excessive vegetation

 

Project Benefits:

-         Restoration of natural drains

-         Increased drainage capacity

-         Prevention of pollution of storm water

-         Improvement the aesthetics of drains

 

Project Cost: Rs. 413.76 Lakhs

 

Implementation Structure: SMC shall be responsible for the execution of the required works through EPC contract.

 

Financing Mechanism: Capital cost to be financed by the SMC using funds to raised through grant under JNNURM

 

Time Frame: 12 months

 

Institutional Responsibility: SMC

 

Preparatory Activity for Implementation:

Preparation of Detailed Project Report

 

Related Programme, Plan and Policies:

 

Additional Studies:

Preparation of Integrated Storm Water Drainage Plan for Shimla Planning Area.

 

 


 

 

Project Title: Construction of roadside drains as per drainage design

 

Project Description: SMC and PWD shall construct roadside drains for length of 54 km. as per drainage design specifications. The drains shall be of a composite drain that have conduits for all cables ducts and provision for pipes and other utility services

 

Project Benefits:

-         Improved capacity of road side drains

-         Improvement in aesthetics of road

-         Delineation of service for utility services

 

Project Cost: Rs. 810 Lakhs

 

Implementation Structure: SMC and PWD shall implement the integrated storm water drainage plan under respective roads through EPC contract, O&M cost may be recovered from utility users

 

Financing Mechanism: Capital cost to be financed by SMC and PWD using funds to raised through grant under JNNURM; O&M cost to be borne by SMC & PWD

 

Time Frame: In synchronous with development of roads and utility services

 

Institutional Responsibility: SMC and PWD

 

Preparatory Activity for Implementation:

Preparation of Detailed Project Report

 

Related Programme, Plan and Policies:

 

Additional Studies:

 

Preparation of Drainage Master Plan for Shimla Planning Area