Comparative Analysis of Water Quality between the Runoff Entrance and Middle of Recycling Irrigation Reservoirs

Abstract

Recycling irrigation reservoirs (RIRs) are an emerging aquatic ecosystem of critical importance, for conserving and protecting increasingly scarce water resources. Here, we compare water quality between runoff entrance and middle of four RIRs in nurseries in Virginia (VA) and Maryland (MD). Surface water temperature (T) and oxidation-reduction potential (ORP) were lower in the middle than at the entrance, while the trend was opposite for dissolved oxygen (DO), pH and chlorophyll a (Chla). The magnitude of these differences between the entrance and middle decreased with increasing depth. These differences were magnified by water stratification from April to October. Minimum differences were observed for electrical conductivity (EC), total dissolved solids (TDS) and turbidity (TUR). Cluster analyses were performed on water quality difference data to evaluate whether the differences vary with respect to reservoirs. Two clusters were OPEN ACCESSWater 2015, 7 3862 formed with one consisting primarily of VA reservoirs, and the other consisting mostly of MD reservoirs in both years. Water quality in the middle and at the entrance of RIRs was expected to vary greatly because of runoff inflow. The two-point water quality differences observed here, although statistically significant, are not large enough to cause significant impact on crop health and productivity for most water quality parameters except pH. Additional analysis of outlet data shows that the range and magnitude of water quality difference between the middle and the outlet are comparable to those between the middle and entrance of RIRs. These results indicate that monitoring at a single point is sufficient to obtain reliable water quality estimates for most water quality parameters in RIRs except pH. This is important when considering the cost of labor and equipment necessary for documenting water quality in agricultural production systems. However, additional pH measurements are still necessary to make practical water quality management decisions.

Monthly Levels and Criteria Considerations of Nutrient, pH, Alkalinity, and Ionic Variables in Runoff Containment Basins in Ornamental Plant Nurseries

“…Zhang et al (2015bZhang et al ( , 2016 showed annual seasonal vertical variations in water quality of some of these same RCBs, stratification being the most prominent event. However, the importance of which variable contributes to water quality variation differs per season and per waterway (Ouyang et al, 2006;Piñol et al, 1992;Zhang et al, 2015bZhang et al, , 2016. In addition, seasonal differences between spring and summer would be confounded by fertilizer practices (fertilizer type, time of application, and rate) and the effect of temperature and rainfall on release rates of CRFs.…”

“…The stream (VA10) is a local natural water source that does not receive runoff from the nursery, thus used as a comparison with VA11, VA12, and VA13. Descriptions of MD and VA RCBs and stream have been previously published using the same label designation (Zhang et al, 2015a(Zhang et al, , 2015b(Zhang et al, , 2016. A description of MS11 was previously described in Copes et al (2015) where it was labeled M2.…”

“…(as much as two units), lower dissolved oxygen (DO, as much as 2.8 mg · L -1 ), and higher oxidative-reduction potential (ORP, as much as 290 mV) than in the middle of the RCB (Zhang et al, 2015b). In addition, pronounced vertical differences can occur from about April to October when thermal stratifications form.…”

Water Use and Treatment in Container-Grown Specialty Crop Production: A Review

“…Removal efficacy for nitrogen in FTWs ranges from 25 to 89%, while phosphorus removal efficacy ranges from 4 to 79% (Lynch et al 2015 ; White and Cousins 2013 ; Zhang et al 2015 ). Plant uptake of nutrients is a pertinent mechanism driving nutrient remediation within FTWs.…”

Nutrient, pH, Alkalinity, and Ionic Property Levels in Runoff Containment Basins in Alabama, Louisiana, Maryland, Mississippi, and Virginia Ornamental Plant Nurseries

“…Ornamental and vegetable plant production operations may have several sources of water, such as open waterways (e.g., streams, rivers, and lakes) and subterranean water sources (e.g., aquifers and wells), that are used for irrigation. The homogeneity or heterogeneity of water quality from open waterways, including RCBs, results from the physical dynamics of the water body that influences the extent of mixing or layering of water (Chiandet and Xenopoulos, 2016;Song et al, 2013;Zhang et al, 2015aZhang et al, , 2015bZhang et al, , 2016. The consideration of withdrawing water from an RCB for plant irrigation requires knowing the range of water properties within the water body, so levels can be predictably managed to produce quality plant material for commercial sales.…”