Lawn irrigation with domestic wastewater by subsurface drip or sprinkling

To maintain the quality of a lawn and allow it to perform its functions (esthetics, enhancement of property, reduction of air temperature, etc.) efficient use of irrigation and adequate fertilization are necessary. The use of wastewater from sewage treatment, which has a nutrient load, in irrigation, can be an alternative especially if applied via subsurface, to reduce contamination risks. This study was conducted to examine the development and quality of an ornamental lawn of Zoysia japonica Steud (zoysiagrass) irrigated with wastewater depths, by two methods. The experiment was carried out in Botucatu-SP, Brazil, during winter and spring (June to December 2016). The treatments consisted of two irrigation methods (sprinkling and subsurface drip) and four domestic-wastewater irrigation depths (50%, 100%, 150% and 200% of the average daily evapotranspiration) plus control, where treated water was supplied by the Basic Sanitation Company of São Paulo State (Sabesp) of Botucatu, SP, Brazil, replacing 100% of average daily evapotranspiration. The following characteristics were studied: clipping dry matter weight, relative chlorophyll content, lawn height, total coliforms and Escherichia coli in the plant tissue and nutrient concentration in the leaves. Subsurface drip irrigation with wastewater, using an irrigation depth of 100% of the average evapotranspiration, allowed an adequate development of the zoysiagrass lawn by maintaining its quality, without contamination by total coliforms or Escherichia coli.

Considering Streamflow Trend Analyses Uncertainty in Urbanizing Watersheds: A Baseflow Case Study in the Central United States

Assuming pro rata reductions in baseflow resulting from urban development may not be valid in all urbanizing watersheds. Anthropogenic offsets or compensatory contributions to baseflow (e.g., net exfiltration from sewer lines, wastewater effluents, and lawn irrigation) may mask or confound fundamental changes in hydrologic pathways. These offsets illustrate the complexities of urban flow processes and the need for improved understanding to mitigate urban development impacts. The authors used two dissimilar automated baseflow separation algorithms and Monte Carlo techniques to evaluate urban baseflow and estimation uncertainty using data from a representative urban watershed in the central United States. Three uncertainties affecting trend determinations were assessed, including algorithm structure, precipitation–runoff relationships, and baseflow algorithm parameterization. Results indicate that, despite ongoing population growth and development, annual streamflow metrics in the authors' representative watershed have not significantly increased or decreased (p > 0.05) from 1967 to 2010. However, several streamflow metrics featured shallow insignificant (p > 0.05) slopes in the direction hypothesized for an urbanizing (less pervious) watershed, including a downward slope for baseflow index (BFI) and increases in runoff volume coefficient. Median annual baseflow estimations differed by 29% between techniques (85.3 versus 118.9 mm yr−1). In the absence of direct tracer measurements, uncertainties associated with precipitation–runoff relationships, algorithm structure, and parameterization should be included in analyses evaluating alterations from baseline hydrologic conditions in urban watersheds. To advance application of separation algorithms for urban watersheds and support regulatory reductions in runoff volume, future work should include calibration of model parameters to available hydrogeologic and tracer data.

In-ground Irrigation Systems Affect Lawn-watering Behaviors of Residential Homeowners

Urbanization is increasing the land area covered with turfgrasses, which may have implications for water quantity and quality. The largest sector of turfgrass is residential lawns. Our objectives were to compare lawn-irrigation perceptions, knowledge, and behaviors of residential homeowners with and without in-ground sprinkler systems (IGS and NIGS, respectively); homeowners were surveyed in three Kansas cities, each with distinctive water quantity and quality issues. Surveys were mailed to 15,500 homeowners in Wichita, 10,000 in Olathe, and 5000 in Salina; the return rate was 11% to 13%. Homeowners with IGS watered more frequently than NIGS; 67% to 90% of IGS and 19% to 31% of NIGS homeowners watered two to three times per week or more. More IGS homeowners watered routinely and applied the same amount of water each time than NIGS homeowners, who mostly watered and adjusted watering amounts based on lawn dryness. More IGS than NIGS homeowners wanted their lawn green all the time, followed lawn-care guidelines, and considered their neighborhood appearance important. Among IGS homeowners, 41% to 54% claimed to know how much water their lawns required compared with only 29% to 33% of NIGS homeowners. However, 65% to 83% in both groups did not know how much water they applied when they irrigated. About 7% to 9% of homeowners swept or blew clippings or lawn-care products into streets or storm drains; this percentage was unaffected by whether they had IGS or not. All homeowners’ lawn irrigation knowledge and habits must be improved to help conserve water and protect water quality, but educational efforts should concentrate on IGS homeowners because they water more frequently.

Automation of size fractionation to extract clays and silts

The objective of this study was to build an automated size fractionator to process up to 16 samples at one time. Most parts used in the apparatus are inexpensive items, available from lawn irrigation, household appliance and aquatic pet supply stores. The device can be used to extract different silt and clay fractions by changing sedimentation time. A bentonite, a kaolin and an ironoxide-rich Oxisol were fractionated by this instrument to sequentially extract particles that have sizes equivalent to <2 µm, <5 µm, <10 µm and <20 µm quartz spheres. A laser diffraction particle size analyser revealed size differences in the different fractions and also showed that the silt fractions contained particles having slightly larger sizes than the assumed diameters of spherical quartz. Scanning electron microscope examination suggested that the greater particle size was mainly due to the non-spherical shapes of the particles and a reduced bulk density of the porous aggregates.

Energy Efficient Homes: The Irrigation System

FCS-3274, a 10-page illustrated fact sheet by Melissa B. Haley, Michael D. Dukes, Stacia Davis, Mary Shedd, and Bernard Cardenas-Lailhacar, describes strategies and technologies for efficiency in home lawn irrigation systems. Includes references. One of an Energy Efficient Homes series. Published by the UF Department of Family Youth and Community Sciences, June 2008.