It is also known as the Pinnate drainage pattern. There are a number of sub rivers that feed the main river and these sub rivers appear like branches. Sometimes, these tributaries also have further tributaries of their own.

Dendritic patterns, which are by far the most common, develop in areas where the rock (or unconsolidated material) beneath the stream has no particular fabric or structure and can be eroded equally easily in all directions. Examples would be granite, gneiss, volcanic rock, and sedimentary rock that has not been folded.

Drainage patterns

• Dendritic drainage pattern.
• Parallel drainage pattern.
• Trellis drainage pattern.
• Rectangular drainage pattern.
• Radial drainage pattern.
• Centripetal drainage pattern.
• Deranged drainage pattern.
• Annular drainage pattern.

Dendritic drainage pattern developed on flat-lying limestone in central Yemen.

A dendritic drainage pattern is the most common form and looks like the branching pattern of tree roots. It develops in regions underlain by homogeneous material. That is, the subsurface geology has a similar resistance to weathering so there is no apparent control over the direction the tributaries take.

The Four Types Of Drainage Systems For Your Home

• Surface Drainage System.
• Subsurface Drainage System.
• Slope Drainage System.
• Downspout and Gutter Systems.
• Contact All Aspects Waterproofing For Your Drainage Needs!

There are two main types of drainage system options: surface drains and french drains. Surface drainage systems consist of a few ground-level areas drains that are connected to PVC piping.

There are two types of artificial drainage: surface drainage and subsurface drainage.

• 6.2. 1 Surface drainage. Surface drainage is the removal of excess water from the surface of the land.
• 6.2. 2 Subsurface drainage. Subsurface drainage is the removal of water from the rootzone.

open deep drainage

Regardless of surface characteristics, when it comes to surface drainage, slope is the most important issue to consider. For efficient drainage, paved surfaces should have a minimum 1-percent slope. Turf or landscaped areas should have a minimum slope of 2 percent.

Requirements of Highway Drainage. The side drain should have sufficient capacity and longitudinal slope to carry away all the surface water collected from the roadway. Flow of surface water across the road and shoulders and along slopes should not cause erosion or form cross ruts.

All above ground and below ground horizontal drainage pipes should be laid to an adequate gradient. Gradients from 1 in 40 to 1 in 110 will normally give adequate flow velocities. A gradient of 1 in 80 is suitable for commencing calculations for pipe schemes.

Drainage Gradients Falls

1. FALL = GRADIENT X DISTANCE.
2. Invert Levels.
3. The level at the crown of the pipe = the invert level + internal diameter of the pipe + pipe wall thickness.
4. Manholes can be manufactured from masonry or precast concrete.

In order to carry the flow and to avoid blockages, the drain or sewer that you intend to connect to generally needs to be at least 0.8m lower than the ground floor level. If it is less than this, you should seek advice from a builder, architect or drainage engineer.

To calculate the volume of water that needs to be stored, multiply the amount of runoff from each drainage zone by 15. The runoff for each zone was in gallons per minute. Multiplying by 15 minutes leaves you with the amount of gallons to be stored.

4-inch pipe: 3,400 gallons per minute.

1106.2 Size of Storm Drain Piping

PIPE SIZE (inches)	CAPACITY (gpm)
2	34	31
3	87	79
4	180	163
5	311	234

The term drainage coefficient stands for the theoretical maximum rate of water removed from a field over a period of time. So, for instance, a 1/2 drainage coefficient means that the system can remove 1/2 of an acre inch of water in a day.

Drainage flow modulus is a quantitative characteristic of groundwater flow from unit drainage area (ha). Drainage flow modulus is used to determine the design discharges of drains and collectors provided optimum ameliorative regime is maintained.

Proper slope of gravity drainage and sewer pipes is important so that liquids flow smoothly, which helps transport solids away without clogging. A pipe that is too flat will prevent waste from flowing away.

¼ inch per foot

The highest point of a manhole (or other access chamber) is the cover level (CL), which is the height of the cover above a benchmark level, and the difference between Cover Level (CL) and Invert level (IL) is the overall depth of the chamber.

Multiply the length of the pipe (x) by the inches needed to slope the line (y) This equals height difference (z) between the beginning and end of the pipe (x) ⋅ (y)=(z) Example: If your pipe is 10 feet, and it needs to slope ½ an inch per foot, the equation would be 10 ⋅ ½ = 5 inches.

1% as a decimal is 0.01 and hence the slope is 0.01. That means for a run of pipe of a certain length the rise must be 0.01 times the length. Thus for you example, since the length of the run is 80 feet which is 80 × 12 = 960 inches the rise must be 0.01 × 960 = 9.6 inches.

For 4-inch PVC piping and a building sewer less than 50 feet long, the minimum slope is 1 inch in 8 feet, or 1/8-inch per foot, and the maximum is 1/4-inch per foot. For sewers longer than 50 feet, the slope should be 1/4-inch per foot.

It’s fine to have a larger-radius (sweep) 90-degree bend at the base of a vertical drainage stack where the wastewater starts to travel horizontally. It’s also a good idea to have a sweep 90-degree fitting where a drain pipe pops out of a wall for a kitchen, vanity or laundry sink. Don’t forget about pipe slope.

1/40

A cleanout shall be installed above the fixture connection fitting, serving each urinal, regardless of the location of the urinal in the building. Exceptions: (1) Cleanouts shall be permitted to be omitted on a horizontal drain line less than 5 feet (1524 mm) in length unless such line is serving sinks or urinals.

A drain cleanout provides access to your main sewer line and is located outside of your home in the front or back yard. Cleanouts typically go unnoticed until there is a problem. They look like capped pipes sticking a few inches above the ground.

Re: tee into cleanout? Bob, under the Uniform Plumbing Code, a cleanout fitting is not to be used for connection of a drainage pipe. A sanitary tee should be installed for the drain pipe connection. You will also need to install a vent to protect the sink’s trap.