Landscape Irrigation Research Articles

Relating spatial turfgrass quality to actual evapotranspiration for precision golf course irrigation

AbstractGolf courses are increasingly affected by water scarcity and climate change. An understanding of spatial variability of actual evapotranspiration (ETa) and turfgrass quality (TQ) site‐specific management zones (SSMZ) is important for the implementation of precision turfgrass management. Therefore, the main objectives of this study were to quantify the relationship between remotely sensed TQ and ETa estimates and to evaluate the spatial variations of TQ and ETa at a golf course in Utah. Ground‐based normalized difference vegetation index was collected using a TCM‐500 sensor, and aerial multispectral and thermal imagery data were acquired from unpiloted aircraft systems (UAS) in 2021, 2022, and 2023. A remote sensing TQ‐random forest (RF) model was developed using six datasets of UAS spectral indices and the RF algorithm. The spatial data were analyzed to determine the correlation between TQ and ETa estimates. The TQ and ETa SSMZ were created and integrated with irrigation heads on the golf course using the Thiessen polygons tool. Results demonstrated that TQ‐RF model was accurate within a root mean square error of 0.05. The correlation between TQ‐RF and ETa was stronger for fairways (R2 = 0.74), tees (R2 = 0.66), and roughs (R2 = 0.75) as compared to greens (R2 = 0.25) and the driving range (R2 = 0.36) on July 20, 2022. Actual evapotranspiration SSMZ, in combination with TQ‐RF SSMZ, is useful for irrigation scheduling, addressing the question of how much and where to irrigate. This study demonstrates the ability of TQ‐RF and ETa SSMZ to identify spatial variation for the purpose of landscape irrigation management in semi‐arid areas.

RECYCLING OF DOMESTIC AND INDUSTRIAL WASTEWATER USING VERMIFILTRATION TECHNOLOGY

One of the biggest problems of our time is the growing shortage of fresh water. According to the World Health Organization, by the middle of the 21st century, half of the planet's inhabitants will experience an acute shortage of fresh water. Simultaneously with the growing consumption of clean water, the annual volume of wastewater from municipal, agricultural and industrial enterprises also increases. At the same time, the volume of water used annually is more than an order of magnitude higher than the volume of treated wastewater. Untreated wastewater is characterized by a high content of organic impurities and pathogenic microorganisms capable of causing diseases that are dangerous for human life. In connection with the outlined extremely urgent task is to ensure effective purification of wastewater from pollution with subsequent recycling of purified effluents - their reuse for other purposes: in the circulating system of industrial enterprises, agricultural and landscape irrigation systems. From this point of view, the process of vermifiltration - wastewater treatment using earthworms - is of great interest. The technology is based on the ability of worms to work as "biofilters". Worms absorb organic and inorganic pollutants from wastewater, digest them and release them in the form of their excrement (coprolites) into the environment. With such processing, wastewater is cleaned, disinfected, and detoxified; treated effluents are suitable for reuse. There is also a transformation of organic and inorganic components into organo-mineral fertilizer - vermicompost and biomass of earthworms, which can serve as raw materials for the fodder and pharmaceutical industry.

Remote Sensing of Residential Landscape Irrigation in Weber County, Utah: Implications for Water Conservation, Image Analysis, and Drone Applications

Analyzing irrigation patterns to promote efficient water use in urban areas is challenging. Analysis of irrigation by remote sensing (AIRS) combines multispectral aerial imagery, evapotranspiration data, and ground-truth measurements to overcome these challenges. We demonstrate AIRS on eight neighborhoods in Weber County, Utah, using 0.6 m National Agriculture Imagery Program (NAIP) and 0.07 m drone imagery, reference evapotranspiration (ET), and water use records. We calculate the difference between the actual and hypothetical water required for each parcel and compare water use over three time periods (2018, 2021, and 2023). We find that the quantity of overwatering, as well as the number of customers overwatering, is decreasing over time. AIRS provides repeatable estimates of irrigated area and irrigation demand that allow water utilities to track water user habits and landscape changes over time and, when controlling for other variables, see if water conservation efforts are effective. In terms of image analysis, we find that (1) both NAIP and drone imagery are sufficient to measure irrigated area in urban settings, (2) the selection of a threshold value for the normalized difference vegetation index (NDVI) becomes less critical for higher-resolution imagery, and (3) irrigated area measurement can be enhanced by combining NDVI with other tools such as building footprint extraction, object classification, and deep learning.

Microbial Treatment Targets for Potable and Nonpotable Water Reuse - A Comprehensive Update and Harmonization.

Increasing pressures on traditional sources of water have accelerated the adoption of water reuse throughout the world. A key consideration for communities pursuing water reuse is understanding the amount of treatment that is needed to ensure adequate human health protection. Several U.S. EPA documents describe the importance of managing acute microbial risks and highlight the utility of quantitative microbial risk assessment for developing "fit-for-purpose" treatment targets based on the source of water and end-use. However, there are no U.S. federal water reuse regulations and states are currently considering microbial treatment targets for various applications. Previous publications have yet to address this need by using an updated and consistent set of input parameters to present risk-based microbial treatment targets across a wide range of sources of water, end-use applications, and health benchmarks. This work combines the most current modeling inputs and dose-response parameter values to provide probability of infection and disease burden-based microbial treatment targets for untreated municipal wastewater, untreated onsite wastewater, graywater, stormwater, and roof runoff water used for potable reuse, indoor nonpotable use, and landscape irrigation applications.

Application of Decentralized Wastewater Treatment Technology in Rural Domestic Wastewater Treatment

The management of domestic wastewater in rural areas has always been challenging due to characteristics such as the wide distribution and dispersion of rural households. There are numerous domestic sewage discharge methods used in rural areas, and it is difficult to treat the sewage. To address this problem, decentralized wastewater treatment systems (DWTSs) have been installed around the globe to reuse and recycle wastewater for non-potable uses such as firefighting, toilet flushing, and landscape irrigation. This study compares the currently implemented treatment processes by investigating them from the point of view of their performance and their advantages and disadvantages to provide new ideas for the development of rural wastewater treatment technologies. According to conventional treatment technologies including activated sludge (OD, A/O, A/A/O, SBR), biofilm (biofilter, MBBR, biological contact oxidation, biofluidized bed) and biogas digesters, natural biological treatment technologies including artificial wetlands (surface flow, vertical flow, horizontal submerged flow artificial wetlands), soil percolation systems (slow, fast, subsurface percolation and surface diffusion) and stabilization pond technology and combined treatment technologies are categorized and further described.

Southern California land surface temperature differences under different landscape composition

AbstractIn the last decade, due to prolonged and persisting drought conditions, California initially restricted water for outdoor landscape irrigation, and subsequently offered turf removal rebates to homeowners. Nevertheless, the effects of turf removal on land surface temperature (LST) in the region have not been investigated. Temperature differences between artificial and natural turf were assessed over time across four counties in Southern California using MODIS/ASTER airborne simulator (MASTER) with a spatial resolution of 5–50 m. Moreover, airborne thermal imagery (submeter spatial resolution) was acquired over selected areas of the city of Riverside, CA, during the summers of 2018 and 2019, including neighborhoods with different income levels, and temperatures for natural turf, artificial turf, and xeriscape were recorded. Environmental and socioeconomic data were compared to the LST in different neighborhoods. Results showed that the LST difference between artificial and natural turf increases in Southern California moving from coastal region to inland. Airborne thermal imagery in Riverside confirmed that University of California artificial turf fields are irrigated during the summer to allow athletes to use the pitch. No correlation between socioeconomic factors and LST of turf and artificial turf fields (and paired differences) was found. On a city scale, natural turf lawns were consistently cooler than xeriscape and artificial turf lawns, closely mirroring mean air temperature. Socioeconomic factors do not describe LST in residential lawns, as warmest and coolest lawns regardless of vegetation are found evenly distributed among different income neighborhoods. Turfgrass removal for water conservation may have unforeseen environmental side effects.

Evaluation of a Greenhouse Ecosystem to Treat Craft Beverage Wastewater

An aerated greenhouse ecosystem, often referred to as a Living Machine®, is a technology for biological wastewater treatment within a greenhouse structure that uses plants with their roots submerged in the wastewater. This system has a small footprint relative to traditional onsite wastewater treatment systems and constructed wetland, can treat high-strength wastewater, and can provide a high level of treatment to allow for reuse for purposes such as irrigation, toilet flushing, and landscape irrigation. Synthetic and actual craft beverage wastewaters (wastewater from wineries, breweries, and cideries) were examined for their treatability in bench-scale greenhouse ecosystems. The tested wastewater was high strength with chemical oxygen demands (COD) concentrations of 1120 to 15,000 mg/L, total nitrogen (TN) concentrations of 3 to 45 mg/L, and total phosphorus (TP) concentrations of 2.3 to 90 mg/L. The COD, TN, and TP concentrations after treatment ranged from below 125 to 560 mg/L, 1.5 to 15 mg/L, and below 0.25 to 7.8 mg/L, respectively. The results confirm the ability of the aerated greenhouse ecosystem to be a viable treatment system for craft beverage wastewater and it is estimated to require 54 and 26% lower hydraulic retention time than an aerobic lagoon and a low temperature, constructed wetland, respectively, the types of systems that would likely be used for this type of wastewater for onsite locations.

Participatory Approach to Irrigated Landscape Ecosystems Boundary Determination: Use of Transect Walk and Focus Group Discussion

Participatory Approach to Irrigated Landscape Ecosystems Boundary Determination: Use of Transect Walk and Focus Group Discussion

Understanding Florida Residents’ Perceptions of and Experiences with Landscape Irrigation Restrictions: Insights for Water Conservation Experts as Well as Extension Educators

Understanding Florida Residents’ Perceptions of and Experiences with Landscape Irrigation Restrictions: Insights for Water Conservation Experts as Well as Extension Educators

Assessment of the effectiveness of a full-scale trickling filter for the treatment of municipal sewage in an arid environment: Multiple linear regression model prediction of fecal coliform removal

In response to water scarcity, Morocco faces the challenge of using treated wastewater for irrigation purposes. This study evaluates the efficiency of a full-scale trickling filter (TF) system in Imintanout, Morocco. The system consists of three septic tanks, two TFs, and secondary decanters. Over a 5-year period, the system showed significant reductions in pollutants: 98 % of TSS, 94 % of BOD5, 98 % of COD, 41 % of TP, and 88 % of NH4+, with these reductions being statistically significant at the 95 % confidence level. A multiple linear regression (MLR) model successfully predicted the removal of fecal coliform (FC) by the TF, and a reduction of 2.88 log units was achieved. High cos2 values indicated the importance of hydraulic loading rate (HLR), BOD5, and FC, which were particularly affected by seasonal variations. Positive correlations between FC and TSS in certain periods highlight the seasonal variability in the composition of urban wastewater, which is effectively captured by the MLR model (R2 = 0.77). Although the treated water complied with Moroccan discharge standards, its high nitrate (140 mg L−1) and FC (4.32 log units) levels made it unsuitable for reuse in agricultural and landscape irrigation, as they exceeded safety limits. This work highlights the importance of optimizing treatment systems to produce high quality reclaimed water, which is essential to meet the challenges of water scarcity.

Application of Multi-Temporal and Multisource Satellite Imagery in the Study of Irrigated Landscapes in Arid Climates

The study of ancient irrigation is crucial in the archaeological research of arid regions. It covers a wide range of topics, with the Near East being the focus for decades. However, political instability and limited data have posed challenges to these studies. The primary objective is to establish a standardised method applicable to different arid environments using the Google Earth Engine platform, considering local relief of terrain and seasonal differences in vegetation. This study integrates multispectral data from LANDSAT 5, Sentinel-2, SAR imagery from Sentinel 1, and TanDEM-X (12 m and 30 m) DSMs. Using these datasets, calculations of selected vegetation indices such as the SMTVI and NDVSI, spectral decomposition methods such as TCT and PCA, and topography-based methods such as the MSRM contribute to a comprehensive understanding of landscape irrigation. This paper investigates the influence of modern environmental conditions on the visibility of features like levees and palaeo-channels by testing different methods and parameters. This study aims to identify the most effective approach for each case study and explore the possibility of applying a consistent method across all areas. Optimal results are achieved by combining several methods, adjusting seasonal parameters, and conducting a comparative analysis of visible features.

Using a soil moisture sensor-based smart controller for autonomous irrigation management of hybrid bermudagrass with recycled water in coastal Southern California

There is a lack of information on the reliability of smart soil moisture sensor-based irrigation controllers for autonomous urban landscape irrigation management using recycled water where water conservation is required, which is the main objective of this study. A three-year turfgrass irrigation research trial (2019–2021) using tertiary-treated recycled water (mean EC = 1.18 dS/m, pH = 7.5) was conducted in Irvine, California, USA. A total of 12 irrigation treatments were designed, including six soil moisture-based thresholds (for triggering and terminating irrigation events) × two irrigation frequency treatments (restricted versus on-demand). Weekly NDVI and canopy temperature data were collected during the summer irrigation season to assess the impact of irrigation treatments on the overall health and quality of 'Tifgreen 328' hybrid bermudagrass. Soil salinity and sodium adsorption ratio (SAR) were measured before and after the summer irrigation seasons. Findings revealed statistically significant effects of irrigation levels and irrigation frequency restrictions on NDVI over the three years. The temperature difference (dT) between turfgrass and air (Tc - Ta) was significantly affected by irrigation levels throughout the three years, while irrigation frequency restrictions showed a significant effect in the years 2021 and 2022. On-demand irrigation resulted in a 10% reduction in temperature difference values during the study period compared to restricted irrigation. Variations in soil salinity levels were observed during the experimental periods; however, both salinity and SAR increased as the study progressed. Results indicate that fully autonomous hybrid bermudagrass irrigation with recycled water, based on recommended soil moisture thresholds of 75% of field capacity over an extended period in a semiarid climate, may lead to unacceptable turfgrass quality.

Highly sensitive passive sampling of new pollutants in urban reclaimed water using hydrophilic-lipophilic balance sorbent-embedded cellulose acetate membrane

Urban reclaimed water is important water resource in China, while the residual new pollutants in the water largely challenge their safety for further use. China's action program for the management of new pollutants (also known as emerging contaminants) requires effective method for monitoring diverse new pollutants in water. This work proposed a highly sensitive passive sampling method for monitoring diverse new pollutants in urban reclaimed water. Hydrophilic–lipophilic balance sorbent-embedded cellulose acetate membranes (HECAMs) were dynamically deployed in self-developed continuous flow integrative sampling device (CFISD) for sampling four types of new pollutants with wide polarity ranges (1.11 < log Kow < 9.49) in a reclaimed water network for landscape irrigation in Beijing, China. The estimated equilibrium partition ratios of most chemicals between HECAM and water were over 104, which would provide low detection limits. In the 7-d high-efficiency deployment, thirty new pollutants were detected, which indicated incompletely removal of various new pollutants in wastewater treatment process. The dynamical accumulation data were successfully fitted by first-order kinetic model and different contaminants reached different accumulation phases in the HECAMs during 7 d. Acceptable and steady uptake rate constants and sampling rates were obtained with the use of CFISD in field sampling. The estimated time-weighted average concentrations for contaminants had wide concentration range and were from 0.03 ng L−1 (pendimethalin) to 3,394 ng L−1 (dibutyl phthalate) and this may lead to environmental risk for further use the reclaimed water. Dynamical deployment results also provided sensitive information of concentration fluctuations and twelve pollutants showed concentration fluctuations during the sampling period. In summary, HECAM showed high sensitivities and credible performance of monitoring diverse new pollutants in the urban reclaimed water.

Enhancing pollutant removal efficiency in urban domestic wastewater treatment through the hybrid multi-soil-layering (MSL) system: A case study in Morocco.

This paper evaluates the performance and potential of a full-scale hybrid multi-soil-layering (MSL) system for the treatment of domestic wastewater for landscape irrigation reuse. The system integrates a solar septic tank and sequential vertical flow MSL and horizontal flow MSL components with alternating layers of gravel and soil-based material. It operates at a hydraulic loading rate of 250 L/m2/day. Results show significant removal of pollutants and pathogens, including total suspended solids (TSS) (97%), chemical oxygen demand (COD) (88.57%), total phosphorus (TP) (79.93%), and total nitrogen (TN) (88.49%), along with significant reductions in fecal bacteria indicators (4.21 log for fecal coliforms and 3.90 log for fecal streptococci) and the pathogen Staphylococcus sp. (2.43 log). The principal component analysis confirms the effectiveness of the system in reducing the concentrations of NH4, COD, TP, PO4, fecal coliforms, fecal streptococci, and fecal staphylococci, thus supporting the reliability of the study. This work highlights the promising potential of the hybrid MSL technology for the treatment of domestic wastewater, especially in arid regions such as North Africa and the Middle East, to support efforts to protect the environment and facilitate the reuse of wastewater for landscape irrigation and agriculture.

Efficient IoT -Machine Learning Based Smart Irrigation Using Support Tree Algae Algorithm

The utilisation of irrigation, one of the most water-intensive agricultural techniques worldwide, has grown in popularity over time. Smart irrigation methods are comparatively innovative technologies that improve domestic landscape irrigation plans, reducing water usage and potential contamination. The primary determinant of agricultural output is soil moisture, and irrigation management depends on a precise estimate of this criterion. The decision-making tool for Irrigation Schedule Prediction available in Machine Learning (ML) plays a crucial role. The drawbacks of traditional machine learning techniques are that they don't predict future values, reduce relative error, and decrease the effective estimation of soil moisture. To overcome the above-said drawbacks, we proposed a machine learning-based SupportTree Algae Algorithm (STAA) to presage soil wetness for smart irrigation. Our proposed STAA method consists of a hybrid approach of Support Vector Machine (SVM) and Decision Tree (DT)classifier incorporated with Artificial Algae Optimization. Our proposed method simulated and achieves 99.5% accuracy, 98.4% precision, 97.5% specificity, and 99.2% Sensitivity when compared with existing methods, namely Random Forest (RF), Fuzzy Logic, and K-Nearest Neighbour (KNN). As a result, a novel STAA method ensured better performance concerning Precision, Sensitivity, Accuracy, Relative Error, Root Mean Square Error (RMSE), Mean Square Error (MSE), Mean Squared Logarithmic Error (MSLE), and Specificity over existing methods.

Beyond awareness: the persuasion stage of decision-making explains urban residents’ compliance with landscape irrigation restrictions

ABSTRACT Inadequate compliance with landscape irrigation restrictions poses a significant challenge for policymakers, environmental educators, and communicators working in urban water conservation as these policies are only effective if compliance is achieved. This study examined perceptions among Florida, USA residents to whom these policies apply using the Diffusion of Innovations Theory. Among the approximately half of these residents who were aware of these restrictions and had an opportunity to develop perceptions about them, perceptions were moderately positive with compatibility, observability, relative advantage, trialability, and complexity falling between 0.0 and 1.0 on a scale ranging from −2 to + 2. Hierarchical linear regression revealed complexity, compatibility, and relative advantage were significant predictors of intention to comply. Perceived complexity was found to be the biggest barrier to individuals’ intent to comply. Policymakers and others working in urban water conservation need to simplify both irrigation restrictions and education about them.

Ensuring microbial water quality for on-site water reuse: Importance of online sensors for reliable operation

A growing number of cities and regions are promoting or mandating on-site treatment and reuse of wastewater, which has resulted in the implementation of several thousand on-site water reuse systems on a global scale. However, there is only limited information on the (microbial) water quality from implemented systems. The focus of this study was on two best-in-class on-site water reuse systems in Bengaluru, India, which typically met the local water quality requirements during monthly compliance testing. This study aimed to (i) assess the microbial quality of the reclaimed water at a high temporal resolution (daily or every 15 min), and (ii) explore whether measurements from commercially available sensors can be used to improve the operation of such systems. The monitoring campaign revealed high variations in microbial water quality, even in these best-in-class systems, rendering the water inadequate for the intended reuse applications (toilet flushing and landscape irrigation). These variations were attributed to two key factors: (1) the low frequency of chlorination, and (2) fluctuations of the chlorine demand of the water, in particular of ammonium concentrations. Such fluctuations are likely inherent to on-site systems, which rely on a low level of process control. The monitoring campaign showed that the microbial water quality was most closely related to oxidation–reduction potential (ORP) and free chlorine sensors. Due to its relatively low cost and low need for maintenance, the ORP emerges as a compelling candidate for automating the chlorination to effectively manage variations in chlorine demand and ensure safe water reuse. Overall, this study underscores the necessity of integrating treatment trains, operation, and monitoring for safe on-site water reuse.

Effect of landscape irrigation regulations on runoff volume from low-density residential catchments during two California droughts

The severe drought in California (2012–2016) generated significant public and government concern. State and local watering regulations were enacted to reduce residential and commercial water-use during the droughts. This study presents a comparison of residential runoff volumes before and after local landscape irrigation regulations were enacted during the droughts of 2008 and 2012–2016. Each sampling site (Folsom 1 and Folsom 2) was a storm drain outfall that drained a low-density residential catchment in the City of Folsom. Dry season runoff measured at the sampling sites represents neighborhood outdoor water waste, mainly from landscape irrigation. During the drought of 2012–2016, median runoff flows were significantly reduced after local landscape irrigation regulations were enacted. The daily runoff pattern was also highly influenced by regulation, with reductions of daily peak runoff flows on 4–5 days in a week after watering regulations were enacted. The number of peak flow events in the daily runoff pattern were reduced during this period. In addition, a significant reduction in mean runoff volume occurred. Based on these results, the watering regulations enacted by the City of Folsom had a positive effect on reducing urban runoff from residential neighborhoods during the dry season. As the results are from monitoring sites in a relatively small geographical area, further work should evaluate reductions in irrigation runoff from other California locations to determine if this is a localized phenomenon.

Modelling Southern Mesopotamia Irrigated Landscapes: How Small-scale Processes Could Contribute to Large-Scale Societal Development

Modelling Southern Mesopotamia Irrigated Landscapes: How Small-scale Processes Could Contribute to Large-Scale Societal Development

The Long-Term Performance of a Rainwater Harvesting System Based on a Quasi-Bicentennial Rainfall Time Series

The University of Genova (Italy) maintains a historical meteorological station that has provided daily rainfall measurements over a quasi-bicentennial period since 1833. The daily rainfall series is analyzed here to assess the impact of long-term precipitation trends on the performance of a rainwater harvesting system. The collected rainwater is used for the irrigation of urban green areas. A behavioral model is applied, involving a dedicated procedure to evaluate the actual soil water content available for vegetation and its decay over time. Non-dimensional indicators are obtained to support adaptation strategies and the sustainable design of the required storage tank. Since both irrigation demand and available water storage depend on the amount of rainfall received, fluctuations in daily rainfall and their trend do affect the performance of the system in a non-trivial way. The results demonstrate that the installation of an RWH system for landscape irrigation is a reliable and resilient solution, at least considering the measured rainfall variations of the last 200 years. In the town of Genoa, no specific adaptation seems necessary in terms of the design of the storage tank other than the usual oversizing, typical of engineering design, to account for uncertainties in the hydrological assessment of any RWH system.