Scope HydroSystems-KDI was asked to prepare an irrigation system master plan of the University of Nebraska – Kearney’s (UNK) Irrigation, Water Supply, and Pumping systems, and to make recommendations of replacements and/or upgrades. The intent of this review is to include overall site irrigation water use require- ments, pumping system requirements, Control System (scheduling) and existing supply piping requirements to meet the primary goal of resource conservation. That is, to provide no more than the precise amount of water necessary to sustain plant materials throughout the site as efficiently as possible. After reviewing this report the site operator should have enough information to outline and implement a usable plan for integrating the included requirements to more efficiently irrigate the campus. If the recommended equipment is installed, long-term savings will be obtained from applying only water required for the plant material based on the seasonal requirements resulting in less yearly water con- sumption, and less electrical energy used for the water supply pumps. This report only addresses the implementation of these existing water resources. No alternative water sources were investigated, but adding wells to replace city water taps is an alternative that will provide resource independence and lower water costs to the university over time.
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There are 23 irrigation system controllers on campus which are not con-
M. Irrigation Most of the UNK campus is served by landscape irrigation. Kearney is located near the intersection of two climatic zones “humid continental” to the east and “semi- arid” to the west. The natural vegetation is grassland with few trees except within floodplains. Adding irrigation water to the campus has made the current green landscape possible. Numerous healthy mature trees and expanses of green grass are the dominant landscape type and they are a significant part of the university’s character and appeal. Goals of the plan include maintaining existing trees, expan- sion of some turf areas, the addition of native grass areas, implementation of a new plant list, and modification of the irrigation system to better serve existing and proposed landscapes. At the same time, significant changes to the irrigation system are recommended.
nected electronically. Recommendation: install a Central Control System with 2-wire decoder wiring throughout campus. The existing Pumping systems are large submersible single motor fixed speed type. The pumps current configuration requires that they operate in their high flow range continuously or they risk being damaged by operating on too low a flow at high pressure. The pumps currently do not have up to date protections and alarms that are available to minimize down time or allow for proper schedul- ing. Recommendation: replace pump controls. 3.
4. The existing backflow preventers are Vacuum Breaker type requiring they be installed 12’’ above the highest irrigator. This has many of the existing devices
2’, 3’ and 4.5’ (Conrad Hall) above the ground and highly visible. Recommendation: replace backflow preventers and add enclosures.
5. The zones that were operated seemed to have average and probably oper- ate at 50%--60% efficiency. Due to time constraints, only a small percentage of zones were operated for evaluation. The newer areas had the desired head to head coverage that allows for shorter run times. Recommendation: re-design and replace inefficient and aging systems. The Pump #2 irrigation controller had three zones wired together operat- ing at once to meet the current pump flow requirement, (see note 2 above). One was a part circle rotor zone, one a full circle rotor zone and one a pop-up spray zone. These all apply water at different precipitation rates and require different run times to apply the same amount of water evenly (scheduling). Recommendation: Upgrade pump controls, revise area irrigated by each pump. 6.
All calculations that pertain to irrigated areas include estimated values and should be confirmed prior to preparing designs for new or existing irrigation systems.
Standard Terminology and Values
One cubic foot = 7.48 gallons of water One acre-foot = 325,828 gallons of water One cubic foot per second (cfs) = 448 gallons per minute (gpm) One acre of Bluegrass Turf requires approximately 30.0” (814,500 gallons) of water per year gpm = gallons per minute
UNK Irrigation
Attachments
Table ‘A’ – Proposed Seasonal Water Use Table ‘B’ – Existing Seasonal Water Use
Goals for the landscape irrigation system guideline include: • Updating and constructing more efficient irrigation systems that also maximize the use of well water. • Implementing new system-wide Design Standards. • Installing a Central Control System. This guideline includes an evaluation of the existing campus landscape irrigation system and recommendations to improve it over time. The areas shown are taken from the physical layout shown on the Landscape Master Plan. As the plan chang- es with future implementation projects, this guideline’s recommendations should be adjusted accordingly.
Exhibit ‘A’ – Proposed Tap and Service Area plan Exhibit ‘B’ – Proposed Controller and Mainline Plan Exhibit ‘C’ – Existing Tap, Controller and Service Plan
Existing Irrigation Evaluation and Recommendations After reviewing the existing campus landscape and irrigation on site with the UNK staff, the following conditions were identified. Recommendations are noted for each and are further explained within this report. Existing campus irrigation systems, with the exception of the Central Utili- ties Plant site and the area immediately around the College of Education building, are older than their 15 to 20 year projected useful life. Recommendation: replace all aged systems. 1.
UNK Backflow Preventers
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Chroma Design Inc.
University of Nebraska - Kearney Campus Landscape Master Plan
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