Rain gardens have become a widespread stormwater practice in the United States, and their use is poised to continue expanding as they are an aesthetically pleasing way to improve the quality of stormwater runoff. The terms rain garden and bioretention, are now often used interchangeably to denote a landscape area that treats stormwater runoff. Rain gardens are an effective, attractive, and sustainable stormwater management solution for residential areas and urban green spaces. They can restore the hydrologic function of urban landscapes and capture stormwater runoff pollutants, such as phosphorus (P), a main pollutant in urban cities and residential neighborhoods. Although design considerations such as size, substrate depth, substrate type, and stormwater holding time have been rigorously tested, little research has been conducted on the living portion of rain gardens. This paper reviews two studies—one that evaluated the effects of flooding and drought tolerance on the physiological responses of native plant species recommended for use in rain gardens, and another that evaluated P removal in monoculture and polyculture rain garden plantings. In the second study, plants and substrate were evaluated for their ability to retain P, a typical water pollutant. Although plant growth across species was sometimes lower when exposed to repeated flooding, plant visual quality was generally not compromised. Although plant selection was limited to species native to the southeastern U.S., some findings may be translated regardless of region. Plant tissue P was higher than either leachate or substrate, indicating the critical role plants play in P accumulation and removal. Additionally, polyculture plantings had the lowest leachate P, suggesting a polyculture planting may be more effective in preventing excess P from entering waterways from bioretention gardens. The findings included that, although monoculture plantings are common in bioretention gardens, polyculture plantings can improve biodiversity, ecosystem resilience, and rain garden functionality.

Greywater is a renewable irrigation alternative to potable water; however, its use as an irrigation source is limited by the potential for salt injury to plants. Research was conducted to determine salt tolerance of three common landscape species, small anise tree (Illicium parviflorum), ‘Henry’s Garnet’ sweetspire (Itea virginica), and muhly grass (Muhlenbergia capillaris). Two experiments were performed, one with high sodium chloride (NaCl) concentrations and one with low NaCl concentrations. Plants received daily irrigation of tap water containing one of the following NaCl concentrations: 0 (tap water); 2000, 4000, 6000, 8000, or 10,000 mg·L−1 (high NaCl); or 0 (tap water), 250, 500, or 1000 mg·L−1 (low NaCl) for 15 weeks. Plants were harvested after 5, 10, or 15 weeks. Root dry weight (RDW) and shoot dry weight (SDW) were determined at each harvest; survival was determined at experiment termination. Leaf tissue was analyzed for tissue macronutrient [nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and, magnesium (Mg)], sodium (Na), and chlorine (Cl) concentrations in the high NaCl concentration experiment. With high NaCl, RDW and SDW decreased with increasing NaCl for all species. Anise and sweetspire had low or no survival, respectively, at the highest NaCl concentration; muhly grass had 100% survival regardless of treatment. In general, leaf macronutrient, Na, and Cl increased with increasing NaCl concentration. With low NaCl, there was no effect of NaCl concentration on RDW or SDW for all species. All three species continued to grow between harvest dates in the lower NaCl concentration experiment, whereas only anise and muhly grass continued to grow with high NaCl. Anise and muhly grass were tolerant of saline irrigation that could be expected from greywater. Sweetspire exhibited symptoms of salt stress (necrotic leaves and leaf drop, visual observation) at all NaCl concentrations including the lowest (250 mg·L−1), and should not be irrigated with saline water.

The initial abstraction ratio (λ) used in the SCS-CN method plays an important role in calculation of runoff volume and consequently hydrograph peak. The recommended value for λ in the SCS handbook is 0.2. However, recent studies suggest that λ varies between 0.05 and 0.2, closer to the lower bound. Yet, the SCS recommended value of 0.2 is still being widely used in many hydrologic models. In this study, we explored the effects of variation in λ on simulating urbanization impacts in a coastal Alabama watershed with HEC-HMS. The potential impacts of future development scenarios on peak flows were scrutinized for λ values of 0.2 and 0.05. Results showed that the use of λ = 0.05 provides superior results when model generated hydrographs and peak flows were compared to observed counterparts.

Marine spatial planning (MSP) is a tool for managing and improving marine environments. The field is dominated by natural scientists and has not been commonly associated with planning. This research analyzes the MSP literature to explore how planners can contribute to MSP research and practice. We organize the literature into eight themes, focusing on how planners may be able to contribute to MSP research and practice: ocean zoning, defining boundaries, planning in dynamic environments, stakeholder involvement, information needs, integrating ocean and land-use management, managing multiple and conflicting uses, and transboundary institutional structures. We conclude that planners have a lot to contribute in these eight areas.

Research was conducted to evaluate the effect of phosphorus (P) concentration in irrigation water on growth of a southeastern U.S. native grass Muhlenbergia capillaris in flooded and non-flooded conditions. Plants of Muhlenbergia capillaris (Lam.) Trin. (gulf muhly grass) growing in 3.8 liter (1 gal) containers in 85:15 sand:peat were flooded to the substrate surface for 0 (non-flooded) or 3 days (flooded). Between flooding events, plants were drained for 6 d with no additional irrigation. The flood-drain process was repeated five times. Non-flooded plants were hand watered as needed. Plants were irrigated (non-flooded) or flooded with one of several tap water solutions, each with a different P concentration ranging from 0 to 0.8 mg·liter−1 (ppm) P (hereafter referred to as P irrigation rate). The experiment was repeated once (total two runs). Shoot dry weight (SDW) root dry weight (RDW) were higher in non-flooded plants than in flooded plants in both runs. Shoot dry weight increased linearly with an increasing P irrigation rate, while RDW changed cubically with increasing P irrigation rates in run 1 (no effect on either in run 2). Phosphorus concentration in leachate increased with increasing P irrigation rate in run 1 but not in run 2. Phosphorus concentration in leachate was usually higher in flooded plants than in non-flooded plants in both runs. All plants maintained root and shoot growth when flooded suggesting M. capillaris would be appropriate native species for rain gardens or bioretention areas. Phosphorus concentrations in leachate were lower than what was applied indicating P was removed via plant uptake or substrate adsorption or both.