Storm Water Systems: All You Need To know
What is Storm water?
Storm water is any type of precipitation that runs off a surface such as roofs, sidewalks, parking lots or roads into which it cannot seep. As cities expand and more roads, parking lots, and buildings are constructed, the way in which precipitation run-off can move through the landscape becomes more important and challenging. The water cannot remain on the surface without causing potential damage or diminishing the structural integrity of buildings and other manufactured surfaces. As a result, systems have been developed and engineered to manage storm water as it rains and snows.
What is a Storm Water SystemStorm water runoff management is an intricate system that many of us take for granted on a daily basis. It exists throughout our communities to maneuver rainfall and other collected water to collection basins and away from our residences and often mini ROVs like the Deep Trekker DTG3 are used to inspect these systems. There are many reasons why this water must be transported away, the main reason is to avoid flooding. For a brief moment, let's look at the basics of the water cycle: As you may notice in this diagram, this is a completely natural environment. Regular surface runoff cannot occur once buildings, roads and other impermeable surfaces are constructed. This disrupts the water cycle and causes a variety of issues. The solution is to transfer the water in a similar pattern mechanically. Here is a diagram of a storm water system: An important note to make from this is that the storm water and sewer lines are separate. The storm water falls as precipitation, flows over buildings and roads into the manholes where it then travels through pipe networks to storage basins and into natural or man made ponds or lakes. These man made lakes should not be mistaken for natural recreation areas; though wildlife may flourish around an open storm water basin, the water is often contaminated with oil from car drippings, pesticides from residential lawns and sediments of heavy metals especially around industrial areas (USEPA 2001). This water is not treated or used for drinking purposes generally because of these contaminants.
There are many precautionary measures besides the drainage network to prevent storm water from mixing with our drinking water resources, especially where our cities and roads are located directly adjacent to reservoirs. Here are some additional features throughout our cities that you may not realize are for storm water management:
Minimizing Directly Connected Impervious Areas - City planners will try to include a grassed area between a road and a water source. Grass lawns or other permeable, biological surfaces naturally filter some of the contaminants through the soil before the water finds its way into the aquifer.
Concrete Grid pavement - Voids in pavement allows the storm water to percolate through to permeable materials and then be filtered naturally.
Grassed Swales - Shallow, vegetated ditches directly beside roads that reduce the speed and volume of the runoff. Filtering can occur but the swales must shallow enough that they do not collect water to a point of being a small basin themselves.
Buffer Strips - Combinations of trees, shrubs and grasses planted along a stream. These strips should consistent of three zones: four to five rows of trees, then two rows of shrubs and finally 20 to 24 feet of wide grass. This reduces the velocity of the runoff and removes a good portion of solids before mixing with drinking water.
Filter Strips - Gently sloping vegetated areas surrounding a surface body of water. These hold the soil in place and act as a filter before storm water reaches the body of water.
Storm Water Ponds or Wetlands - Permanent ponds where solids settle between storms are created to collect the water. Storm water drainage efforts in surrounding areas are directed to the pond. These ponds often are used as visual features in communities or parks. The damage to the environment is minimal if managed properly and if the sediment is removed every seven to ten years.
Infiltration Practices - Narrow, stone-filled excavated trenches. These are deeper than grassed swales, the three to twelve feet deep trenches store runoff between the stones and slowly infiltrate the soil. When combined with other pre-treatment practices such as a swale, this method has been found to filter up to 98% of contaminants.
Swirl-type Concentrators - Underground vaults that are designed to create circular motion, creating sedimentation and oil and grease removal. The currents rapidly separate out settleable grit and floatable matter.
The cumulative effects of runoff being left unchecked can be dangerous. Inspection of each part of the storm water management system is key to maintaining the water cycle balance over the long term. Deep Trekker ROVs are used to inspect these networks. If do you have a system that's overdue for an inspection, contact us to hear how we can help you.
Why is managing storm water so important?
There are two significant reasons why managing storm water is important. The first is faster runoff. When it rains or snows in the city with numerous roads and buildings and storm water management systems excess water is evacuated these much faster than if the rain had simply fallen in a natural environment.
In the wilderness rain lands and slowly seeps back into the earth. In a city, there is much faster runoff from the constructed surfaces on which it lands. This in turn creates even larger volumes of water flowing to and within surrounding creeks and rivers. Increased volume can lead to erosion, damaged stream banks and beds, local flooding, undercut roads and stress on building foundations.
Water creates a significant force against any structure it is contained by and it is the main catalyst of erosion, corrosion and weathering. Pipes do not rest or recover, they are under constant pressure from water's weight and movement. Even the strongest materials, such as concrete and steel, damage over time. This damage leads to leaks and breaks. These leaks at best are a waste of our most precious resource. It is estimated that the United States loses almost 8 trillion liters of water a year to leaks
In the case of storm water system leaks, the contaminated water leaks into our water table and environment. The risk of storm waterways leaking is our drinking water can be contaminated and the storm water is misplaced when it could have been used for irrigation, industrial purposes, etc. after treatment. Both our drinking water and valuable storm water sources are squandered when the system breaks down.
Secondly, storm water needs to be managed because it also acts as a pollutant transport. Rainwater does not originate from a single source like a discharge pipe, so as it flows across various surfaces picking up all manner of impurities (oil from the roads, fertilizers, car materials etc.) and carry it to nearby streams and river.
Why are regular storm water management inspections important?
As with any structural system, regular inspections to ensure the integrity of the pipes/drains/basins are important. Pipelines can encounter a number of issues that need to be tended to on a regular basis. Blocked pipes, leaks, cracks, and sediment build up are some of the common challenges that face pipeline flow systems. Cracks, leaks and weak structures can cause problems to the entire management system.
By performing regular inspections of storm water systems including the inflows, outflows, manholes, internal pipes and water basins, municipalities and contractors can rest assured that all is well and the system is operating at its full capacity. If something is wrong with the system, the longer it sits the deficiencies often multiply and compound.. By completing frequent inspections, maintenance workers can address issues as soon as they are recognized.
How do we prevent these leaks? Prevention begins with inspection. Knowing the condition of the water network is the first step to planning; what areas of the network are more severely damaged than others. If a small repair is caught early on, the fix will be less costly and time consuming. It will also reduce the volume of leakage.
The Implications of Mismanaged Storm Water
It is also important to understand what the dangers of storm water in large quantities is to your city, health and environment. If a storm water management system has many flaws it can have major impacts on drinking water, structures and ecosystems.
There are three primary concerns associated with poorly managed or uncontrolled storm water runoff:
During a time of increased peak discharge (high precipitation rates and winds), the conditions create higher volumes of water. These higher volumes of water are unable to penetrate through roads and buildings, leading to the full volume of the rainfall to sit at the surface and expand its volume. The high volumes of water cause initial flooding and then the more damaging effect is the winds and increased velocity of the water. As the water gains volume, it gains weight and the combined forces of gravity and wind move the water faster and faster. The impermeable surfaces do not slow the water at all. Large volumes of water moving at a fast pace leads to erosion once they encounter permeable ground. Erosion has many implications, causing structural damage, rerouting rivers and streams to create future flooding issues and compounding these effects.
Reduction in Recharge
Impermeable surfaces means the rainfall is unable to infiltrate the ground, which leads to the depletion of the ground water. The uncontrolled runoff does eventually find a home, more often than not, somewhere besides an aquifer or reservoir. These fresh water sources are depleted for drinking water consumption but two sources of replenishment (groundwater runoff and direct runoff) are cut off.
Runoff water that does not infiltrate the ground through soil is not afforded the chance to be filtered of pollutants. Worse, as it travels across roads, lawns and construction sites, it collects car oil drippings, fertilizers and sediment. Once the water reaches a destination, it has either collected into a pool of unwanted water (flooding) that is full of pollutants and is dangerous for animals and people alike or it has polluted a larger body of fresh water.
Urban storm water runoff is regularly found with 77 of the 127 priority pollutants. This water is not easily distinguishable as it enters our water table and aquifers, we cannot simply depend on water treatment processes to filter all of the pollutants, as some pollutants would not be targeted by its processes. The priority should be to implement more storm water management practices in areas that do not have them and make regular inspection part of the maintenance of a city's water network.
Where Does Deep Trekker Come In?
Storm Water pipes are usually between 15 and 60 inches and have large amounts of sediment settled at the bottom. The sediment is stirred by a diver or crawler vehicles, making visualization nearly impossible.
There are also usually only an access point within meters or even kilometers of each other. This a confined space that is dangerous for a diver.
The cost associated with a dive team also makes it difficult for many local governments to afford routine inspections. Often these systems are just ignored and networks are left to break down over time.
The SolutionDeep Trekker ROVs are the perfect solution for these storm water systems.
Deep Trekker builds robust underwater inspection systems in the form of pipe crawlers and mini-remotely operated vehicles (ROVs). All Deep Trekker products are completely portable with on-board lithium batteries that provide 4-8 hours of run time, enough to do an entire inspection day’s work. The designed emphasis on portability and quick deployment means no additional components such as generators or dedicated service trucks are required. This also results in significant cost reductions and the ability to easily inspect in more remote areas.
The DTG3 ROV system is the perfect tool to perform storm water basin inspections. Deep Trekker ROVs are built using a patented pitching system that allows the ROV to fly up, down, side to side, back and forth with only two thrusters. It is extremely easy to use and is operated with a game-style pad controller housing an integrated super bright viewing screen. Inspectors have everything at hand to monitor and inspect any system with ease.
A great example is Morris-Riley Development Management LLC, a Florida area asset management company that services a storm water irrigation system home to over 6,000 homes, 1,000,000 acres of commercial space and two golf courses. They use their two DTG3 ROVSto inspect every inch of the entire network.
The DTG3's compact and spherical shape allows it to fit into as small as 14 inch pipes, with a 270 degree rotating camera allowing for thorough inspections even within those tight, confined spaces. The low light (0.01 lux) HD camera and high efficiency LED light mounted to the camera allow for inspections of "better than human eye" quality. This is important when entering murky waters with no direct sunlight.
Morris-Riley ROV pilots are able to lower the ROV by its tether into the pipes through access points, then view the live feed from their 5.6 inch LCD screen on the handheld controller. On extremely bright, sunny days, the pilot uses their Digital Video Recorder , allowing them to document every inch of their inspection. The DTG3 has up to an 8 hour battery life, allowing it to be deployed from even the most remote access points with no generators necessary.
The DT340 Pipe Crawler system is quickly becoming the "go-to" system for storm water pipe and drain inspections. With various wheel sizes and track options, Deep Trekker’s pipe crawler system is designed to effectively operate within a wide variety of pipe size inspections and soil types. The DT340S system sports a pan/tilt/zoom camera, steerable wheels and the same easy-to-use controller found on other Deep Trekker ROV systems.
Like any structural system, the integrity of infrastructure must be monitored and maintained. Regular inspections to ensure the condition of the pipes, drains, basins and other structures are imperative for safe storm water management. Issues like leaks, cracks, blocked pipes and sediment build up are common challenges that should be identified and addressed quickly. Submersible remotely operated vehicles (ROVs) are an effective, easy and cost-saving option for infrastructure inspection.
Deep Trekker’s underwater ROVs provide a safe and cost effective alternative to hiring divers, while pipe crawlers allow operators to explore pipes that are inaccessible to humans. The battery powered robots do not require topside power, making them easily portable and easy to deploy. Powerful cameras provide operators with a complete view of the area they are inspecting while also allowing for inspections to be recorded or photographed for further review. Add ons for the underwater ROVs and the pipe crawlers give operators advanced options such as laser scalers, Cygnus thickness gauges, and elevating arms.
Municipalities and contractors can be confident that they are providing the best possible storm water management system with regular inspections of key structures. Inflows, outflows, manholes, internal pipes and water basins must all be inspected regularly to ensure that they are operating at full capacity to prevent issues. Frequent inspections are key, as deficiencies can often multiply and compound as time goes by. By conducting consistent inspections, imperfections can be addressed before they become a costly issue.
Learn more about how Deep Trekker ROVs are used in municipalities or reach out to an industry expert today.
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