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Predicting Water Use for Irrigation

Posted by on Oct 24, 2012 in Blog, News | Comments Off on Predicting Water Use for Irrigation

One of the biggest Landtech ‘values’ is when we work with landscape architects and develop an  estimate of what the water needs will be based on their landscape design. With water prices and water scarcity both going up, we are often asked to reduce water use for irrigation purposes. Water harvesting, or collecting rainwater to be used for irrigation by directing it from the roof into a cistern, is a good method for reducing reliance on municipal water supplies. The following is a description of our process for predicting water use for irrigation to help you understand what goes into creating the most water efficient irrigation system possible. Our process begins with what we call “scoping”, which is an exercise that enables us to come up with a recommendation for the optimal size of the cistern needed for water harvesting. This is important to determine because cisterns are the most expensive component of a water harvesting system. You need the cistern to be large enough to collect the rain expected to fall, but you don’t want it to be so big that is will never be full, resulting in money wasted. So how do you know what size cistern is right for a given site? Landtech has a model (below) that helps estimate water use during the peak month of July. Once we know the expected amount of water that will be needed, we give the data to our partner, Wahaso who are experts at water catchment and reuse. Wahaso uses the information to discern the optimal size for the cistern, or water catchment system, based on how much water the site can expect to harvest according the average amounts of rainfall, as well as the area of the roof/surfaces that collect the rainwater. Here is an explanation of the above model: We begin by grouping the site into categories based on the water needs of the plants and turfgrass. Group A represents the acreage of turfgrass and lawn areas. We assign each group a weight based on how high the needs are for watering the area. Group A is weighted at 100% meaning it has the highest needs of all groups, and therefore placed at the top of list for watering priority. Group B is the next most demanding group, representing the amount of acres for the highly visible/more-public areas. This is weighted at 70% because it can do fine with a little stress, whereas Group A will not and, therefore, needs to receive 100% of the water required. Group C is the acreage of the plant beds, which we deem moderately important, weighting them at 65%. Last, is Group D representing the areas that will require temporary irrigation to enable newly planted trees or plants to get established. This group is given a weight of 60%. The next step is determining the amount of rainfall (RF) to be expected, as well as the amount of rainfall that will be effective (ER), due to slope, plant cover, soils, etc. This reduction is necessary because there will never be 100% of the rain that actually percolates into the ground during/after a rain event. Then, we must consider the evapotranspiration rate (ET) for the area, which refers to the amount of water that evaporates before it can be absorbed + the amount of moisture that transpires from the plants. We then subtract the evapotranspiration amount from the effective rainfall amount to determine the amount of supplemental water required for each group, according to their weighted needs.  Next, an efficiency factor is applied (by Group) to develop an estimated application amount....

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6 Ways to Decrease Water Used for Irrigation

Posted by on Oct 17, 2012 in Blog, News | Comments Off on 6 Ways to Decrease Water Used for Irrigation

With water prices going up along with our awareness of water scarcity, we are often asked how to decrease water used for irrigation.  Here are a few of our tactics for reducing the overall water used by an irrigation system: Reduce Site Water Requirements One of the simplest ways to decrease water used for irrigation is to limit the turf areas that require a high amount of water, along with plants that have moderate to high water needs. Replace plants and turf areas with hearty/native plants that can survive with less water. Improve Distribution Uniformity (DU) Oftentimes, facility managers will run the sprinklers longer if they see that there are dry/brown spots. Not only does this decrease water efficiency, it is ineffective. Dry spots are a result of poor sprinkler head spacing and placement. Distribution uniformity means placing the sprinkler heads properly so that water will be distributed evenly across the entire lawn, or planted area. Using equipment that has a more consistent application rate in turf areas to eliminate dry areas will also work to achieve even distribution of water. Use Pressure Regulation Pressure regulation helps ensure that sprinklers are operating at the optimal level.  When pressure is too high, water droplets atomize, which results in significant amounts of water being carried off-site by wind drift. By reducing the operating pressure, the water drops are larger and heavier, and are more likely to land where intended. Convert to Drip Irrigation Convert sprinklers (within plant beds) over to drip irrigation so water has less of a chance to evaporate and/or runoff. Drip irrigation is about 90-95% efficient, while spray heads and rotors are about 60-65% efficient. Improve Management Practices Make sure property managers remember to check the sprinklers once a week. Since the sprinklers usually operate after work hours, property managers may not know when a sprinkler head isn’t operating properly. A good practice is running the zones once a week to check that the whole system is in working order. Use Smart Controllers Smart controllers determine the watering durations and frequencies on a daily basis based on the real-time weather conditions. They adjust run times based on the needs of all the various plant types; some days, certain zones may not need to run at all.   The controller relies on you to input the correct soil and plant type. It is important to remember that these controllers are only as good as the information you input. If you are considering using a smart controller, you must be able to assess and document the various site features present within each zone (plants, soils, exposure, shade, slope, root depth).  ...

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Rainwater Harvesting Cost and Considerations

Posted by on Oct 10, 2012 in Blog, News | Comments Off on Rainwater Harvesting Cost and Considerations

As one of the oldest known gardening methods, rainwater harvesting is a great option for projects that need to reduce dependence on municipal water supplies and/or practice sustainable irrigation. Rainwater harvesting systems typically consist of three main components: the capture system (roof and gutters) the storage unit (cistern) the delivery system (pipes, pumps, and valves) Materials for the water storage unit are about two-thirds of the overall cost of the whole project, making this the most expensive component of the entire system. That is why it is  important to understand how to determine the optimal size water storage unit for each individual project. If you build too large, the payback will start to decrease. A small scale watering harvesting system for the home or small business would likely opt for a cistern that has less than a 10,000 gallon capacity. This type of system would be a viable use of collecting rain water and filtering it for reuse to water a garden or entrance area. A large scale water harvesting system for large commercial projects is at the other end of the spectrum.  The financial investment for these types of projects is going to be considerably larger. There are a number of factors that need to be considered: What is the size of the area to be irrigated? What is the area of the roof top or surface that will be allocated towards collecting and diverting water to a storage facility? What are the rainfall patterns for the project site? How these factors relate to the overall design of the system will vary in every project. With so many variables to consider, it is difficult to have a standard rule of thumb for projecting costs. But generally speaking, a water system in place and installed is right around 2 dollars per gallon. So for a 150,000 gallon storage unit, you will likely be in the ballpark of $300,000 project. Landtech’s partner, Wahaso (Water Harvesting Solutions, in Chicago) has good data about the rainfall pattern for every part of the country to help answer the questions: What was the amount of rain? How long did it rain? How frequently did the rain events occur? Answering these questions is vital to knowing what size of cistern you will need and how much you can expect to rely on harvested water for irrigation. Let’s say you need 150,000 gallons of water a week for your irrigation, and you live in a location where the amount of rainfall will not be sufficient to fill a 150,000 gallon cistern meaning the cistern would never actually be full. Therefore, spending money on a cistern that large would make a significant impact on the ROI.  A cistern should only be big enough for the amount of rain to be...

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What Does LEED and SITES Mean for Sustainable Irrigation?

Posted by on Oct 3, 2012 in Blog, News | Comments Off on What Does LEED and SITES Mean for Sustainable Irrigation?

Landscape professionals have a major role to play. Among other things, sustainable irrigation can help protect habitat, contribute to storm water management, reduce fossil fuel usage and conserve water. Across the country, green industry providers are lending their efforts in countless ways. Green roofs and walls, rainwater catchment systems, rain gardens, native plantings and no-mow zones are just a few examples. The professionals at Landtech are following suit by shifting the way we think about the future of irrigation. Programs like LEED and SITES have created a whole new way of thinking for us. We have witnessed firsthand how those with expertise in sustainable irrigation can provide high value perspective to developers, landscape architects, engineers and homeowners. Irrigation consultants are playing a valuable role in bettering the environment while at the same time boosting the image of the entire industry. While many in the irrigation industry see the rising trend of construction projects forgoing or minimizing irrigation to gain LEED and SITE credits as a threat, we are looking at this as an opportunity to engage. Efforts to conserve are not a passing fad. As irrigation professionals, we see that we have an important role to play as leaders in this movement. At first touch, LEED and SITE credits seem like a threat to our bottom line. However, the reality is that water is a scarce resource and we, as irrigation professionals, possess front-line knowledge and experience that give us an edge in providing value to the growth of the conservancy movement. LEED projects require a different mindset, and we know the platform of products that effectively  accomplish water conservation. We know what will work best for the specific needs of a project. Addressing irrigation from a design/build approach is usually not effective because irrigation contractors often don’t know what products to use to get LEED or SITE credits. At Landtech, we know exactly what needs to be done to meet the calculations for those water-efficiency credits. As experts in irrigation and devout followers of state-of-the-art technology, we create the right roadmap to get the results that are in demand in this era of green development.          ...

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7 Reasons to Use an Irrigation Consultant

Posted by on Sep 26, 2012 in Blog, News | Comments Off on 7 Reasons to Use an Irrigation Consultant

For many new construction projects in the Midwest and Northeast, irrigation is typically viewed as an overlap of landscaping and therefore usually does not have a well defined plan. Without having a set plan that multiple contractors can use to base their price quotes on, the construction manager gets prices that are based on the individual contractor’s cheapest version of the plan, so the construction manager is not comparing apples-to-apples and is not getting the best irrigation system for the job. With this approach, the construction manager is basing their decision off of who has the lowest bid, not who has the best plan that will meet the long term needs of their clients. This is why hiring an irrigation consultant may be one of the smartest investments a building manager makes in the overall design/build process. Here are seven reasons to use an irrigation consultant: 1. Commercial irrigation systems have become expensive; irrigation technology is sophisticated and can often be confusing. An irrigation consultant is a specialist who is kept up-to-date (by manufacturers), and can design a long-lasting system that is both water and energy efficient. 2. Most consultants are willing to review products with you, and can help you select from a wide array of products on the market. They can help you separate facts from confusing sales claims. 3.  Most importantly, an irrigation consultant can be supportive in the struggle to convince your client (and/or construction manager) to not sacrifice quality, by value-engineering, and substituting-out the most appropriate products that will be long-lasting & efficient, and (when applicable) will enable the project to meet the requirements of LEED and/or SITES. 4. A consultant puts contractors and distributors on an equal footing by impartially specifying the appropriate equipment for the project being addressed. The bids that are submitted will also be more comparable, allowing the decision-makers to compare apples-to-apples. 5. A consultant is aware of project considerations beyond equipment selection: water/power supplies and consumption, location of upfront equipment (backflow preventer, pump-station, mechanical room spatial requirements) plant watering needs, environmental concerns, etc. 6. A consultant can assist the landscape architect/developer in developing accurate budget estimates. 7. An increasingly common involvement is that of water-harvesting.  An irrigation consultant provides a crucial link with the team in being able to provide early preliminary calculations for anticipated water use/demand. This greatly assists in the planning efforts in the programming phase of a project, in determining water-storage chamber sizes & location, and positioning of the necessary mechanical equipment involved. If you would like to learn more, contact Jim Davis at 314-541-2779 or email him...

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