Life form dependent impacts of macrophyte vegetation on the ratio of resuspended nutrients

The effects of floating-leaved and submerged macrophytes on sediment resuspension and on the ratio of resuspended nitrogen and phosphorus were studied by sediment traps in the Kirkkojärvi basin in southern Finland. The effect of submerged macrophytes on preventing sediment resuspension was stronger than the effect of floating-leaved plants. On average, among submerged plants the resuspension rate of suspended solids was 43%, and among floating-leaved plants 87% of that in the open water. The floating-leaved Nuphar lutea had a reductive effect on P resuspension but no significant effect on N resuspension. The impact on P resuspension was strong, because root uptake by Nuphar lutea reduced the P content of the sediment. N:P ratio in resuspended nutrients was 6.7 among the plants and 4.1 in the open water. Among suzbmerged plants, sediment N content was strongly increased but P content was not affected due to the pleustophytic life form of the dominant plants (Ceratophyllum demersum, Ranunculus circinatus). The effect of pleustophytes on sediment nutrients was weak, because their nutrient uptake is mostly foliar. The N:P ratio of resuspended nutrients was 7.9 among the submerged plants and 7.0 in the open water. The results suggested that depending on the life form, macrophytes can modify the flux of N and/or P to the water column through their effects on nutrient resuspension and possibly modify phytoplankton communities via their effects on the N:P ratio. If the overall nutrient level is the most important factor for the dominance of cyanobacteria, submerged macrophytes can have stronger effects on phytoplankton community structure than floating-leaved species. If N:P ratio is of importance, the effects of floating-leaved species may be more pronounced.     

The influence of macrophytes on sedimentation and nutrient retention in the lower River Spree (Germany)

Nutrient retention due to sedimentation in running waters has been little studied. The knowledge about the processes of self-purification is important for the management of rivers. The principal aim of our investigations was to quantify nutrient retention by sedimentation within and adjacent to stands of submerged macrophytes. In addition, we examined the relationship between deposition and sedimentation patterns and the flow regime. In the summer of 2001, investigations were performed in the lower River Spree with sediment traps and sediment cores and measurement of flow velocities. The spatial distribution of macrophytes was described and related to sedimentation and flow patterns. Water and sediment samples were analysed for total phosphorus and total organic nitrogen concentrations. Macrophytes significantly enhanced water residence time by factors between 2 and 18. Trapping rates were high within and downstream of macrophyte stands due to the prevailing quiescent conditions. Trapping rates were low in regions not covered by macrophytes, where flow velocities were high. Calculated deposition of organic matter due to trapping rates accounted for 15-49% of observed deposition between May and September, the vegetation period. The difference between calculated and observed deposition can partly be attributed to an incomplete erosion of the organic sediments between October and April. Between May and September, nitrogen and phosphorus were retained by deposition by as much as 2.5% and 12.2%, respectively (% of total load). Therefore, macrophytes considerably contributed to total monthly phosphorus retention (up to 25%) by increasing deposition of particulate organic matter.     

The phosphorus budget of the Thame catchment,Oxfordshire: 2. Modelling

The phosphorus budget of the River Thame was modelled at a daily time scale, using estimates of diffuse and point source contributions of discharge. The model simulated suspended sediment (SS), soluble unreactive phosphorus (SUP), soluble reactive phosphorus (SRP) and particulate phosphorus (PP) concentrations within the main river and major tributaries. Diffuse source estimates of phosphorus loads were based on characteristic losses from identified main landscape classes, with hydrology described by a simple conceptual storage model. In-stream flow was modelled using a kinematic wave equation. Transfer of suspended sediment and phosphorus components was approximated by advection. In-stream sources and sinks included uptake and release of soluble reactive phosphorus by bed sediment, instant equilibration between SRP and the PP concentration on suspended sediment, and flow-related entrainment and deposition of suspended sediment. Simulations at sites within the catchment were compared with measurements made in 1998–1999. Results showed the P budget is dominated by mixing of diffuse and point source water, but some within-river processes have been shown to be capable of significantly influencing SRP concentrations. The development of a sediment entrainment and deposition component of the model has proved particularly valuable in emulating the hysteretic relationship between discharge and suspended sediment concentration in the river. It also provides a measure of available bed sediment.     

Sediment nutrient characteristics and aquatic macrophytes in lowland English rivers

Aquatic macrophytes play an important role in the nutrient dynamics of streams. As a result, there is much interest in their use as trophic indicators. However, the relationship between aquatic macrophytes and the trophic status of rivers is a complex one, partly because of the effects of a wide range of environmental variables and partly because submerged, rooted macrophytes can absorb nutrients from the river sediments and/or the water column. Experiments which have tried to establish the relative importance of sediments or water as sources of nutrients are inconclusive and further work is needed to establish how sediment nutrient characteristics vary within and among rivers (spatially and temporally) and the inter-relationships between sediment nutrients, water column chemistry and macrophytes. This paper presents the initial findings from a study of 17 lowland rivers in southern England which is exploring the spatial variability of sediment characteristics (total and inorganic phosphorus, total nitrogen, organic carbon, silt-clay fraction and organic matter content) and the relationship with aquatic macrophytes. The preliminary analysis indicates that although sediment characteristics are highly variable within 100-m river reaches, the variability across the 17 rivers is even greater; this is despite the limited geographic and trophic range of the study sites. The results presented in this paper also give some indication of the sediment characteristics associated with five macrophyte species but it is too early to ascribe sediment preferences for particular species.     

Polychlorinated biphenyl pollution caused by resuspension of surface sediments in the lagoon of Venice

A mechanical device was used to reproduce in the laboratory the sediment resuspension caused by tidal currents and wind waves in the lagoon of Venice. Shear stresses comparable to those observed in the field were applied to the sediment surface. Series of experiments were run at 6.6 and 9.0 dyn/cm2. The concentration of polychlorinated biphenyls (PCBs) were determined in the sediments and resuspended particulate matter by means of gas chromatographic techniques. At the two different stresses, particulate matter with different grain size and different concentrations of PCBs was resuspended. However, no significant differences were observed in the amounts of PCBs mobilized per litre of water. In fact, by increasing the applied stress, coarser particulate matter was resuspended with a lower concentration of PCBs per unit of dry weight.     

Modeling sediment impact on the transport of fecal bacteria

Sediment storage of fecal bacteria has been observed for a long time. However, limited modeling efforts have been conducted to dynamically and explicitly study the impact of sediment on the transport of fecal bacteria. In this paper, a modeling framework based on the Environmental Fluid Dynamics Code (EFDC) model has been proposed. Free and particle-associated fecal bacteria can be modeled explicitly using the developed model. A linear adsorption relationship is incorporated into the model to obtain a sediment concentration dependent attachment ratio. The deposition and resuspension fluxes of fecal bacteria across the sediment bed–water interface are calculated coupled with the sediment deposition and resuspension flux. The model was applied to hypothetical scenarios to evaluate the sediment impacts under ideal settling and resuspension conditions. A case study was provided to test the resuspension calculation of fecal bacteria under an artificial flooding condition. Using this model, the contributions of fecal bacteria from sediment bed and from the watershed can be modeled separately and explicitly.     

Investigating phosphorus interactions with bed sediments in a fluvial environment using a recirculating flume and intact soil cores

Phosphorus uptake by bed sediments in surface drains can reduce phosphorus exports from irrigated land. This paper reports on an investigation into the effects of velocity and water depth on phosphorus uptake by bed sediments, which consisted of eight sequential flow events conducted in a recirculating flume as well as a concurrent experiment using sediment cores. For the heavy clay bed sediment discussed in this paper, velocity and depth of water column had no significant effect on net phosphorus uptake and the rates of phosphorus uptake in either the cores or the recirculating flume. The most significant factor affecting phosphorus uptake was the experiment number which represented the sequential nature of experiments within the flume and increasing phosphorus saturation of the surface sediments. Of the kinetic equations used to describe phosphorus uptake (Elovich, boundary layer and diffusion) the Elovich equation provided the best representation of the results, both in terms of the adj-R2 values and the absence of systematic errors in the residuals. Results suggest that intact soil cores may be used to parameterise rate equations such as the Elovich equation for use in process-based mathematical models of phosphorus transport in fluvial systems.     

Resuspension and settling of helminth eggs in water: Interactions with cohesive sediments

Helminth parasite eggs in low quality water represent main food safety and health hazards and are therefore important indicators used to determine whether such water can be used for irrigation. Through sedimentation helminth eggs accumulate in the sediment, however resuspension of deposited helminth eggs will lead to increased concentration of suspended eggs in the water. Our study aimed to determine the erodibility (erosion rate and erosion threshold) and settling velocity of Ascaris and Trichuris eggs as well as cohesive sediment at different time points after incorporation into the sediment. Cohesive sediment collected from a freshwater stream was used to prepare a sediment bed onto which helminth eggs were allowed to settle. The erodibility of both sediment and helminth eggs was found to decrease over time indicating that the eggs were incorporated into the surface material of the bed and that this material was stabilized through time. This interaction between eggs and bulk sediment was further manifested in an increased settling velocity of suspended eggs when sediment was present in the suspension as compared to a situation with settling in clean water. The incorporation into the sediment bed and the aggregation with sediment particles decrease the mobility of both helminth egg types. Our findings document that helminth eggs should not be viewed as single entities in water systems when modelling the distribution of eggs since both erodibility and settling velocity of eggs are determined by mobility of the sediment present in the water stream. Recalculation of the erosion threshold for helminth eggs and sediment showed that even at relatively low current velocities i.e. 0.07-0.12 m s⁻¹ newly deposited eggs will be mobile in open irrigation channels. These environmental factors affecting resuspension must be taken into account when developing models for sedimentation of helminth eggs in different water systems.     

Modeling the dry-weather tidal cycling of fecal indicator bacteria in surface waters of an intertidal wetland

Recreational water quality at beaches in California and elsewhere is often poor near the outlets of rivers, estuaries, and lagoons. This condition has prompted interest in the role of wetlands in modulating surface water concentrations of fecal indicator bacteria (FIB), the basis of water quality standards internationally. A model was developed and applied to predict the dry-weather tidal cycling of FIB in Talbert Marsh, an estuarine, intertidal wetland in Huntington Beach, California, in response to loads from urban runoff, bird feces, and resuspended sediments. The model predicts the advection, dispersion and die-off of total coliform, Escherichia coli, and enterococci using a depth-integrated formulation. We find that urban runoff and resuspension of contaminated wetland sediments are responsible for surface water concentrations of FIB in the wetland. Model predictions show that urban runoff controls surface water concentrations at inland sites and sediment resuspension controls surface water concentrations near the mouth. Direct wash-off of bird feces into the surface water is not a significant contributor, although bird feces can contribute to the sediment bacteria load. The key parameters needed to accurately predict FIB concentrations, using a validated hydrodynamic model, are: the load due to urban runoff, sediment erodibility parameters, and sediment concentrations and surface water die-off rates of enteric bacteria. In the present study, literature values for sediment erodibility and water column die-off rates are used and average concentrations of FIB are predicted within 1/2 log unit of measurements. Total coliform are predicted more accurately than E. coli or enterococci, both in terms of magnitude and tidal variability. Since wetland-dependent animals are natural sources of FIB, and FIB survive for long periods of time and may multiply in wetland sediments, these results highlight limitations of FIB as indicators of human fecal pollution in and near wetlands.     

Sediment-water exchange of Vibrio sp. and fecal indicator bacteria: implications for persistence and transport in the Neuse River Estuary, North Carolina, USA

In estuaries, frequent resuspension and deposition of sediment complicate bacterial transport model development by transporting particle-attached bacteria and possibly inducing bacterial responses, such as growth, degradation, or changes in attachment. In order to better characterize these dynamics, observations were made in the Neuse River Estuary (NRE) using the combination of an in situ sampler to monitor the water column and sediment cores to monitor sediment concentrations. Two allochthonous bacteria, Escherichia coli (EC) and Enterococcus sp. (ENT), were selected as proxies for fecal contamination from stormwater runoff. Vibrio sp. (VIB), native to the NRE, was also observed as an autochthonous bacterial group that includes potentially pathogenic species. Two sampling periods were identified as dominated by different suspension types: runoff and resuspension. Despite this difference, several bacterial measures remained comparable between sampling periods. In bottom water, VIB concentration was correlated with salinity and ENT concentration was correlated with turbidity. Differences were observed for EC, where higher concentrations were found in hypoxic waters and sediment during the resuspension period. In the sediment, EC and VIB concentrations significantly increased following the passage of Hurricane Ophelia in September 2005. Throughout this study, all bacterial groups showed evidence of persistence in sediment, suggesting that sediment resuspension represents a significant source of bacteria to the water column.     

Phosphorus release rates from sediments and pollutant characteristics in Han River, Seoul, Korea

The Han River is 469.7-km long and drains a 26219-km(2) watershed. The sediments in the river are highly polluted due to inputs from upstream tributaries as well as partially treated municipal wastewaters that are discharged to the river. The water quality and strategy for control are important because the river is the primary drinking water supply for the City of Seoul, as well as being a major source for irrigation and industrial water. The Jamsil submerged dam partitions the river to isolate an upstream area for drinking water, but also captures sediments. Samples from four sites were studied to determine sediment pollutant concentrations and phosphorus release rates. Phosphorus tends to desorb from sediments when the concentration of overlying water is less than 1.4 mg/l. Water column P concentrations range from 0.04 to 0.1 mg/l, which suggests that sediments will act as a P source. In a series of batch experiments, P was released at approximately 15-20 mg/m(2)week in the winter (1-5 degrees C) and as much as 90 mg/m(2)week in the summer (20-24 degrees C), and is also a function of pH and dissolved oxygen concentration. The sediment total phosphorus concentration, which averages 833 mg/kg, is evenly distributed among non-apatite-P (33%), apatite-P (32%) and residual-P (34%). An equilibrium model is proposed to describe release rate.     

Sediment phosphate composition in relation to emergent macrophytes in the Doñana Marshes (SW Spain)

We have studied the effect of the presence of emergent macrophytes on the sediment phosphate composition of a eutrophic shallow marsh on the NE margin of Do?ana (SW Spain). Top sediment and water samples were collected from both the open-water and the vegetated sites at three areas covered by different plant species: Scirpus maritimus, Juncus subulatus and Phragmites australis. The concentration of organic matter was significantly higher in the top sediment of sites covered by vegetation than in their adjacent open-water sites at the three vegetation areas. The P-fractional composition showed that the sediment was dominated by the inorganic P-fractions in all cases, reaching the highest concentration in the Ca-bound P-fraction (281-372 microg g(-1) d.w.). The sum of all P-fractions was significantly higher in the top sediment of the sites covered by J. subulatus and S. maritimus than in their adjacent open-water sites, and so were the org-P fraction extracted by hot NaOH and the concentration of phytate within this fraction. Deposition of plant material on the top sediment of areas vegetated by J. subulatus and S. maritimus explains these differences. The P-fractional composition of the seeds from J. subulatus showed that they contained a large proportion of organic P-fractions, particularly of the fraction extracted by hot NaOH (1868 microg g(-1) d.w., 85% of which was phytate). The presence of emergent macrophytes, therefore, influenced the distribution of P-fractions in the sediment depending on plant species. The P-bioavailability of shallow aquatic systems must be fully understood if wetlands are to be protected from further eutrophication.     

Long-term (1956-1999) dynamics of phosphorus in a shallow, subtropical Chinese lake with the possible effects of cyanobacterial blooms.

This paper describes the long-term dynamics of phosphorus concentrations in both the lake water and the sediment in a subtropical Chinese lake, Lake Donghu. The total phosphorus (TP) concentration in the lake water experienced an upward trend from the 1950s, and peaked in 1983/1984, but declined obviously afterwards. From the 1950s to thel990s. TP content in the upper 10cm sediment of the lake increased steadily from 0.307 to 1.68mg P gDW(-1) at Station I and from 0.151 to 0.89 mg P g DW(-1) at Station II, respectively. The TP increase in the lake water before mid-1980s was mainly attributed to the massive input of sewage P. The outbreak of cyanobacterial blooms coincided with the peaks of TP and Orthophosphate (PO4-P) in the water in mid-1980s, and the maximum TP of the water reached as high as 1.349mg/l at Station I and 0.757mg/l at Station II (in 1984), respectively. The declines of TP and P04-P in the water after mid-1980s was coincident with the disappearance of cyanobacterial bloom.     

Downward fluxes of particulate carbon, nitrogen and phosphorus in the north-western Adriatic sea

Downward fluxes of particles, organic carbon, total nitrogen and total phosphorus and the composition of the settled particulate matter were determined in the north-western Adriatic Sea at two coastal sites influenced by the outflows of the Po and Adige rivers and one offshore site. Vertical fluxes were strongly influenced by resuspension processes in addition to the primary flux and advection. The resuspended material contributed on average 34-43% of the total matter sedimented in the near bottom traps in coastal waters. Net annual vertical fluxes (due to primary flux and advection) of organic carbon, total nitrogen and phosphorus in the coastal stations were: 71-97 g C m(-2) year(-1), 8-14 g N m(-2) year(-1) and 2.1-2.3 g P m(-2) year(-1), with the highest values recorded at the station off the Po river delta. The offshore site was characterised by net annual fluxes of particulates, C, N and P approximately one order of magnitude lower than the above. The carbon export to the bottom was limited in the warm seasons when it constituted only 2-9% of primary production, due to high recycling and utilisation in the upper layer of the water column, increasing up to 8-18% in winter because of the instability of the water column and low biological utilisation.     

Benthic fluxes of cadmium, lead, copper and nitrogen species in the northern Adriatic Sea in front of the River Po outflow, Italy

Trace heavy metal (Cd, Pb and Cu) and nitrogen species (N-NO3, N-NO2 and N-NH4) fluxes between sediment and water were examined for approximately 4 days, in a coastal marine station located in the northern Adriatic Sea in front of the River Po outflow. An in situ benthic chamber, equipped with electronic devices for monitoring and adjustment of oxygen and pH and with a temperature detector, was used. The benthic chamber experiment enabled study of the temporal trend of metals and nutrients when oxygen concentration varied in a controlled environment. Although particular care was devoted to chamber deposition and parameter control, sediment resuspension occurred at the beginning of the experiment and O2 fluctuations were observed during the course of the experiment. Pb concentration was affected by both resuspension and oxic conditions in bottom water, which prevented determination of any reasonable Pb flux value. Cd and Cu, not influenced by oxygen fluctuations, reached an equilibrium phase in a short period with initial positive fluxes from sediment of 0.68 (S.D. = 0.07) and 6.9 (S.D. = 5.6) pmol cm(-2) h(-1), respectively. With regard to nitrogen species, the highest positive flux was that of N-NH4 (10.5, S.D. = 2.4, nmol cm(-2) h(-1)) whose concentration increased in the chamber, while nitrate concentration (initial flux of -5.7, S.D. = 1.5, nmol cm(-2) h(-1)) immediately decreased after the beginning of the experiment. Nitrite concentration was almost constant throughout the experiment and its flux was generally low (initial flux 0.1, S.D. = 0.9, nmol cm(-2) h(-1)).     

Measuring the trophic status of ponds: Relationships between summer rate of periphytic net primary productivity and water physico-chemistry

The monitoring of the water quality is a major environmental concern and specific method of assessment needs to be addressed for ponds. Among threats on freshwater, eutrophication remains an important and widespread problem. To assess if the trophic state of ponds can be significantly predicted by physico-chemical surrogates, parallel measurements of water physico-chemistry and of summer rates of periphytic net primary productivity (NPP) were performed on a set of nine lowland Swiss ponds representing the whole spectrum of trophic states.The developed methods to measure periphytic NPP on artificial substrates give similar values between the pseudo-replicates and are functional for ponds. The winter concentration of total nitrogen (TN) in the water is a significant predictor of the average summer rates of NPP while in submerged macrophyte beds total phosphorus (TP) is a better predictor. Rates of NPP measured in open water were most often higher and water transparency lower than in macrophyte beds, highlighting the positive influence of macrophytes on water quality and a possible co-occurrence in a pond of contrasting conditions when submerged species are present. This emphasizes the importance of maintaining or restoring submerged macrophyte stands in ponds to improve the water quality.     

The effects of sediment size fraction and associated algal biofilms on the kinetics of phosphorus release

Experiments using flumes containing sediment of three different size fractions, from two sites on the River Tame, investigated the influences of sediment particle size, and an associated biofilm, on sediment-water exchanges in heterogeneous sediment deposits. This is the first study undertaken to understand the kinetics of the release of soluble reactive phosphorus from sediments of natural systems to identify which of the size compartments affected those fluxes most. Samples of fine material (<2 mm), gravel (2-20 mm), and stones (>20 mm) were collected over a period of several weeks and brought to a fluvarium where they were placed in artificial, controlled flow, and flume channels. Synthetic solutions of similar ionic strength to the river were prepared using calcium chloride. Temperature, pH, and dissolved oxygen of the solution overlying the sediment were monitored automatically whilst filtered samples were obtained at 2 h intervals over 48 h. The biomass, expressed as mg m(-2) chlorophyll a, of the algal component of the biofilm from the surface of the sediment was estimated using methanol extraction. Differences in the responses were observed between the sediment size fractions and the two sites, where contaminant concentrations varied. The equilibrium phosphate concentration and a phosphorus transfer index were used to establish that there was a net uptake of phosphorus by all three sediment size fractions, from both sites, at the time of sampling. The kinetic results showed very fast initial reactions of phosphorus release from the larger size fractions with a well-developed filamentous algal growth present implying a different mechanism than diffusion being involved. The stones and associated biofilms also released more phosphorus than the fine fraction, e.g. final release concentrations for the most contaminated site were: fines approximately 2.5 microM, gravel approximately 6.5 microM, and stones approximately 65.0 microM (expressed as soluble reactive phosphorus). Phosphorus fluxes, calculated assuming the concentration of phosphorus in the sediment was less than the equilibrium concentration, were a maximum at the most contaminated site, e.g. fines 6.4 nmol m(-2) s(-1), gravel 27 nmol m(-2) s(-1), and stones 109 nmol m(-2) s(-1) (normalised with respect to the river bed area). These results confirm that sediment having a biofilm and associated particulate material results in a greater flux than fine sediment, which does not support a filamentous biomass. Removal of the fine particulates trapped in the algal growth reduced soluble phosphorus release. These factors demonstrate that both gravel and stone substrates have an important control over the release of soluble reactive phosphorus.     

Seasonal nutrient dynamics in a chalk stream: the River Frome, Dorset, UK

Chalk streams provide unique, environmentally important habitats, but are particularly susceptible to human activities, such as water abstraction, fish farming and intensive agricultural activity on their fertile flood-meadows, resulting in increased nutrient concentrations. Weekly phosphorus, nitrate, dissolved silicon, chloride and flow measurements were made at nine sites along a 32 km stretch of the River Frome and its tributaries, over a 15 month period. The stretch was divided into two sections (termed the middle and lower reach) and mass balances were calculated for each determinand by totalling the inputs from upstream, tributaries, sewage treatment works and an estimate of groundwater input, and subtracting this from the load exported from each reach. Phosphorus and nitrate were retained within the river channel during the summer months, due to bioaccumulation into river biota and adsorption of phosphorus to bed sediments. During the autumn to spring periods, there was a net export, attributed to increased diffuse inputs from the catchment during storms, decomposition of channel biomass and remobilisation of phosphorus from the bed sediment. This seasonality of retention and remobilisation was higher in the lower reach than the middle reach, which was attributed to downstream changes in land use and fine sediment availability. Silicon showed much less seasonality, but did have periods of rapid retention in spring, due to diatom uptake within the river channel, and a subsequent release from the bed sediments during storm events. Chloride did not produce a seasonal pattern, indicating that the observed phosphorus and nitrate seasonality was a product of annual variation in diffuse inputs and internal riverine processes, rather than an artefact of sampling, flow gauging and analytical errors.     

Whole lake responses to low level copper sulfate treatment

The impact of three low level copper sulfate applications to Cazenovia Lake, New York, was assessed through a high frequency monitoring program. Monitored parameters included: (1) filtered and total copper; (2) phytoplankton identification and enumeration; (3) chlorophyll-a, (4) in situ¹⁴C assimilation; (5) bacteria numbers; (6) zooplankton identification and enumeration, (7) macrophyte nutrient status and (8) filtered reactive and total phosphorus.The low level application caused only small increases (maximum of 5 μg/l) of short duration (2–5 days) in filtered copper. The treatments failed to induce effective algicidal action in the target phytoplankton populations of the lake, but they did induce short term stress and alterations in the natural seasonal succession processes within these populations. No definitive responses in the zooplankton, submerged macrophytes or water column phosphorus levels were noted. Dramatic reductions in the water column bacteria occurred immediately following each treatment, indicating direct negative impact. Phytoplankton and bacteria populations recovered within 1 week and several days, respectively.     

五里湖富营养水体生态重建试验

为了改善五里湖水环境,从2002年起,展开对五里湖及其周边地区综合整治、西五里湖生态重建与示范工程。初步结果表明,西五里湖水质得到一定的改善,水体透明度也有所提高,尤其是示范工程区内透明度的平均值比湖区的高1.6倍。最好的水质出现在示范工程区内,与未进行生态恢复的东五里湖相比,水体中的TN、TP、Chl.a、NH4-N及NO2-N均有较大幅度降低,但CODMn、NO3-N、SD差异不大。湖滨生态景观有了较大改善,建立了具有生态景观效果的芦苇、狭叶香蒲、水菖蒲、水生类鸢尾及美人蕉等湖滨湿地近1.0万m2;在敞水区恢复了浮叶、沉水植物超过3.5万m2。通过生态重建实践,对浅水湖泊生态恢复提出了建议。