Geotechnics and Infrastructure
Infrastructure Design: Water Supply, Sewerage and Stormwater
We prepare transmission main, water distribution network, sewerage and stormwater designs based on hydraulic calculations, the existing line data in GIS and the specifications of the authority.
Water supply, wastewater and stormwater lines
We prepare the designs of transmission mains, water distribution networks, sewerage and stormwater lines. We start from an up-to-date site survey map, the existing line data in the authority's GIS and the zoning plan; the hydraulic calculation is built on this data. Once a line is in the ground, the only way to correct a wrong gradient or diameter is to dig it up again. That is why we check the longitudinal profiles one by one with their levels. We work for municipalities, water and sewerage authorities, public bodies, organized industrial zones, housing estate investors and contractors.
In Kocaeli you climb from the gulf shore to the hillsides in a short distance. For water supply this means more than one pressure zone in the same district. In sewerage there are steep collectors on one side, and on the other, stretches along the shore where it is hard to get enough fall and groundwater gets into the trench. In industrial areas the space under the road is often full of electricity, natural gas and telecommunication lines. We set the route together with these lines and prepare the drawings and information required in the AYKOME (infrastructure coordination) process.
For water supply we check separately the static pressure at the hour of lowest consumption and the operating pressure when peak consumption and fire flow are drawn at the same time. In sewerage the velocity must not fall below the lower limit that prevents settling, nor rise to values that would wear the pipe and manholes. The fill ratio limit that leaves part of the pipe empty for ventilation is checked on the same longitudinal profile. For stormwater we do not end the calculation at the discharge point. We also look at whether the receiving stream or channel can take that water, and at the discharge level.
Scope
Transmission mains
On the line from the source or pumping station to the reservoir, we calculate the head losses and the hydraulic grade line and check water hammer. Air valves and washouts are placed at the high and low points of the longitudinal profile.
Water distribution network
We solve the network with population projections and consumption flows. The boundaries of the pressure zones, the pipe diameters and the positions of valves and fire hydrants come out of this solution.
Pipe material selection
HDPE, ductile iron, corrugated or reinforced concrete pipe. The ground in the trench affects the choice as much as the pressure class and the operating needs.
Sewer network
We calculate the wastewater flows and set the velocity and gradient limits, the fill ratio and the manhole spacing according to the authority's specifications.
Stormwater and drainage
We calculate the flow with the rational method, from the rainfall intensity-duration-frequency relationship. We size the collectors, gratings and outfall structures for this flow.
Profiles, details and quantities
Besides the plans and longitudinal profiles, we draw the trench, bedding and backfill details. The cost estimate and quantity schedules are taken from the same drawings.
Applicable regulations and standards
In the calculations and drawings we follow the technical specifications of İller Bankası and those of the water and sewerage authority that will operate the line (İSU in Kocaeli). On treatment and discharge matters we comply with the environmental legislation, and on excavation and routing with the AYKOME coordination rules. We use the TS EN standards below for the design, laying and testing of pipelines.
How we work
Data collection
We collect the site survey map, the GIS-based existing line data, the zoning plan and the authority's opinions. Where the map is missing or out of date, we say at the start that a survey is needed.
Design basis
Before starting the calculation we agree with the authority on the design period, the population and flow assumptions, the pressure zones and the discharge points.
Hydraulic calculations
We carry out the network and line calculations and set out the velocity, pressure, gradient and fill ratio checks line by line in tables.
Route coordination
We mark on the drawings the crossings with other utilities, the road and stream crossings, and the stretches that need expropriation or an easement.
Drawings and quantities
We prepare the plan, longitudinal profile and detail sheets with the cost estimate and quantity schedules and submit them for the authority's approval. We also work in the corrections requested during approval.
Deliverables
- Design report and hydraulic calculation tables
- General site plan and network plan sheets
- Longitudinal profiles (ground level, invert level, gradient, manhole and valve positions)
- Trench, bedding, backfill, manhole and connection details
- Cost estimate summary, quantity take-off and approximate cost schedules
- GIS-compatible drawing data in the digital format the authority requires
Frequently asked questions
Which authority's specifications do you design to?
Those of the authority that will operate the line. In Kocaeli the İSU specifications apply, and for work financed by İller Bankası, the İller Bankası specifications. If the two differ, we ask the authority which one applies before we start.
Do you also design electricity or natural gas lines?
No. We take these lines into account only for route coordination, and mark the crossing and clearance distances on our own design.
Why are sewerage and stormwater designed as separate systems?
For new projects, authorities usually require a separate system. When stormwater is collected in its own line, the treatment plant is not overloaded on rainy days, and wastewater does not come up to the surface during a flood.
How do you choose the pipe material?
By the operating pressure, the diameter, the ground and groundwater conditions, the traffic load and the authority's preference. We write the reason for the choice in the calculation report.
Are the cost estimate and quantity take-off part of the design?
Yes. We take the quantities directly from the drawings. For a tender file we also prepare a detailed cost estimate and approximate cost study.
Request a quote for your project
Write to us with the type of building, its location and the documents you have. We will agree the scope and timeline with you and send a written quote.