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Interim Hydrologic Responses to Phase I of the Kissimmee River Restoration Project, Florida
Abstract
Hydrologic conditions were evaluated during a 10-year Interim Period following completion of Phase I of the Kissimmee River Restoration Project and initiation of environmental water releases from upstream to provide adaptive management of flow to the Phase I area. Phase I construction backfilled 13 km of flood control canal C-38 and redirected flow into 22 km of reconnected river channel. Evaluations focused on five restoration expectations (performance measures) based on pre-channelization hydrologic data for the Kissimmee River. Environmental releases resulted in more continuous discharge from upstream, but did not affect the magnitude of discharge. After backfilling of C-38, water levels in the Phase I area varied with discharge and periodically inundated the floodplain. However, the long, annual recession event, characteristic of pre-channelization, was not reestablished; instead, most Interim Period years had multiple events with shorter durations and faster recession rates. Mean channel water velocity increased during the Interim Period but was not always in the desired range. Hydrologic conditions throughout much of the Phase I area were affected by the backwater effect of the downstream water control structure. Four expectations showed improvements in terms of number of years met; however, none met the expectation targets. The inability to meet expectation targets reflects in part the incomplete or interim status of the restoration project.
... Using a BACIPS (Before-After-Control-Impact Paired Series) experimental design (Stewart-Oaten et al. 1986), monthly aerial surveys were employed to measure dry season (December to May) and wet season (June to November) abundance of long-legged wading birds and winter (November to March) abundance of waterfowl before and after restoration construction (see Bousquin et al. 2005, Chapter 14 for detailed methods). The term post-construction used throughout the manuscript refers to the Phase I restoration area only, and refers only to the restoration of the physical form of the river, not a complete restoration of appropriate hydrology (see Anderson 2014). contains a complete description of the construction phases and a map of Pools A-D. ...
... Since completion of Phase I restoration, the river has experienced a more natural flood-pulse cycle (Koebel & Bousquin 2014 Appendix S4 Photos 5 & 6). In turn, the hydrology, wetland vegetation, fish and invertebrate communities are becoming reestablished and attracting wading birds and waterfowl (Anderson 2014;Koebel & Bousquin 2014 Appendix S4 Photos 4-17;Spencer & Bousquin 2014). Since no large breeding colonies of aquatic wading birds (>500 nests) have yet formed within or near (<3 km) the floodplain, and only two waterfowl species regularly breed in the area, a large proportion of the birds observed within the restored area is likely the result of immigration rather than local reproduction (Melvin et al. 1999). ...
... While reestablishment of the physical form of the river is considered complete within the Phase I restoration area, the Headwaters Revitalization water regulation schedule is not yet in operation and several important aspects of hydrology do not fully mimic the historical flood-recession cycle. In particular, recession events in the Phase I area have started earlier in the year, occurred more frequently, been shorter in duration, and often had higher rates than during the reference period (Anderson 2014). Additionally, increases in discharge of water from the upper basin headwaters has been unseasonably large during the peak of the dry season on several occasions, resulting in stage reversals that can be damaging to wading bird foraging and nesting (Frederick & Collopy 1989;Anderson 2014). ...
Success of the Kissimmee River Restoration Project will
be evaluated in part by monitoring populations of wading
birds (Pelecaniformes and Ciconiiformes) and waterfowl
(Anseriformes). These two waterbird guilds were integral
components of the pre-channelization river–floodplain
ecosystem, and both declined substantially following channelization.
Restoration is expected to attract wading birds
and waterfowl by reintroducing naturally fluctuating water
levels, seasonal hydroperiods, and historic vegetation communities.
Post-restoration aerial surveys (November 2001
to May 2008) within the Phase I restoration area indicate
that the abundance of aquatic wading birds and the
species richness of both wading birds and waterfowl have
shown a positive restoration response thus far. Dry season
abundance of long-legged wading birds and waterfowl has
exceeded restoration expectations (≥30.6 birds/km2 and
≥3.9 birds/km2, respectively) each year since the completion
of restoration Phase I in 2001. While there has
been a significant positive restoration effect on waterfowl
abundance, waterfowl species richness (n =6) has not yet
reached the restoration expectation of ≥13 species. Cattle
egret abundance, which flourished after the majority
of floodplain wetlands were converted to cattle pastures in
the channelized system, has shown a significant negative
response to restoration. It is anticipated that completion of
the remaining phases of restoration (II/III), and implementation
of the Kissimmee River Headwaters Revitalization
water regulation schedule by 2016, will further increase
and improve habitat for wading birds and waterfowl by
reestablishing floodplain hydrology that more closely mimics
historical conditions.
Key words: Florida, monitoring, performance measure,
restoration effect, wading birds, waterfowl, wetland
restoration evaluation, wildlife metrics.
... Phase I construction removed the S-65B WCS and backfilled about 12 km of the C-38 canal with the original material that had been dredged during excavation of the canal, and reconnected remnant channels to reestablish 22 km of continuous historic river channel. Following Phase I, an interim water regulation schedule was implemented to allow improved timing and continuity of inflow from the river's headwater lakes (Anderson 2014). However, this interim schedule does not fully meet the hydrologic requirements of the fully restored system; a revised water regulation schedule called the Headwaters Schedule will be implemented once the final phases of restoration construction and land acquisition are completed (Koebel & Bosquin 2014). ...
... This difference results from a constraint to current hydrologic management in the Phase I area, the presence of the S-65C WCS and its associated tieback levee, which are planned for removal during Phase II/III construction (projected for completion in 2019). Because of the north-south slope of the floodplain, the structure/levee and the associated operational constraints cause almost continuously wet conditions immediately above the WCS and a reduced range of water level fluctuation compared with the northern Phase I area floodplain (Anderson 2014). Anderson (2014) found that water level stabilization extends into the Phase I study area at least as far north as PC32 (Fig. 2); this effect is referred to as a backwater. ...
... Because of the north-south slope of the floodplain, the structure/levee and the associated operational constraints cause almost continuously wet conditions immediately above the WCS and a reduced range of water level fluctuation compared with the northern Phase I area floodplain (Anderson 2014). Anderson (2014) found that water level stabilization extends into the Phase I study area at least as far north as PC32 (Fig. 2); this effect is referred to as a backwater. At the southernmost recorders (PC21 and PC32), aboveground inundation was nearly continuous from 2002 to 2008 (Fig. 6). ...
Phase I of the Kissimmee River Restoration Project
(KRRP) reestablished intermittent inundation of the
river’s floodplain by backfilling 12 km of the C-38 flood
control canal in 2001. We compared floodplain vegetation
maps based on 2003 and 2008 aerial imagery (2 and 7 years
following completion of Phase I, respectively) to vegetation
maps from 1954 (pre-channelization), 1974 (3 years
after channelization), and 1996 (25 years after channelization)
to evaluate broad-scale vegetation responses to
Phase I restoration. Results indicate that the extent of
wetland plant communities expanded rapidly, more than
doubling in area within 2 years after completion of Phase
I, and that by 2008 wetlands had nearly recovered to
pre-channelization levels. However, full reestablishment
of the pre-channelization wetland mosaic has not yet
occurred. Prior to channelization, much of the floodplain
was dominated by a broadleaf marsh (BLM) community
associated with extended, deep annual flooding, while
shorter-hydroperiod communities dominated the floodplain
in 2003 and 2008. Prior to restoration construction,
the reestablishment of BLM was predicted to be slow
because suitable hydrology is dependent on project components
that will not be in place until all restoration
components are completed (projected for 2019). Hydrologic
data indicate that the duration and variability of
floodplain inundation have not yet achieved restoration
targets over the entire Phase I study area. Other factors
affecting vegetation responses are likely involved,
including the age and viability of soil seed banks, the rarity
of relict propagule sources following the channelized
period, and competition from an invasive wetland shrub
species.
Key words: hydroperiod restoration, marsh, restoration
evaluation, vegetation mapping, wet prairie, wetlands.
... Using a BACIPS (Before-After-Control-Impact Paired Series) experimental design (Stewart-Oaten et al. 1986), monthly aerial surveys were employed to measure dry season (December to May) and wet season (June to November) abundance of long-legged wading birds and winter (November to March) abundance of waterfowl before and after restoration construction (see Bousquin et al. 2005, Chapter 14 for detailed methods). The term post-construction used throughout the manuscript refers to the Phase I restoration area only, and refers only to the restoration of the physical form of the river, not a complete restoration of appropriate hydrology (see Anderson 2014). contains a complete description of the construction phases and a map of Pools A-D. ...
... Since completion of Phase I restoration, the river has experienced a more natural flood-pulse cycle (Koebel & Bousquin 2014 Appendix S4 Photos 5 & 6). In turn, the hydrology, wetland vegetation, fish and invertebrate communities are becoming reestablished and attracting wading birds and waterfowl (Anderson 2014;Koebel & Bousquin 2014 Appendix S4 Photos 4-17;Spencer & Bousquin 2014). Since no large breeding colonies of aquatic wading birds (>500 nests) have yet formed within or near (<3 km) the floodplain, and only two waterfowl species regularly breed in the area, a large proportion of the birds observed within the restored area is likely the result of immigration rather than local reproduction (Melvin et al. 1999). ...
... While reestablishment of the physical form of the river is considered complete within the Phase I restoration area, the Headwaters Revitalization water regulation schedule is not yet in operation and several important aspects of hydrology do not fully mimic the historical flood-recession cycle. In particular, recession events in the Phase I area have started earlier in the year, occurred more frequently, been shorter in duration, and often had higher rates than during the reference period (Anderson 2014). Additionally, increases in discharge of water from the upper basin headwaters has been unseasonably large during the peak of the dry season on several occasions, resulting in stage reversals that can be damaging to wading bird foraging and nesting (Frederick & Collopy 1989;Anderson 2014). ...
Success of the Kissimmee River Restoration Project will be evaluated in part by monitoring populations of wading birds (Pelecaniformes and Ciconiiformes) and waterfowl (Anseriformes). These two waterbird guilds were integral components of the pre-channelization river–floodplain ecosystem, and both declined substantially following channelization. Restoration is expected to attract wading birds and waterfowl by reintroducing naturally fluctuating water levels, seasonal hydroperiods, and historic vegetation communities. Post-construction aerial surveys (November 2001 to May 2008) within the Phase I restoration area indicate that the abundance and species richness of both wading birds and waterfowl have shown a positive restoration response thus far. Dry season abundance of aquatic wading birds and waterfowl has exceeded restoration expectations (≥30.6 birds/km2 and ≥3.9 birds/km2, respectively) each year since the completion of restoration Phase I in 2001. While there has been a significant positive restoration effect on waterfowl abundance, waterfowl species richness (n = 6) has not yet reached the restoration expectation of ≥13 species. Abundance of the terrestrial cattle egret (Bubulcus ibis), which increased dramatically after the majority of floodplain wetlands were converted to cattle pastures in the channelized system, has shown a significant negative response to restoration. It is anticipated that completion of the remaining phases of restoration (II/III), and implementation of the Kissimmee River Headwaters Revitalization water regulation schedule by 2019, will further increase and improve habitat for wading birds and waterfowl by reestablishing floodplain hydrology that more closely mimics historical conditions.
... Dechannelization reestablished flood-pulse-driven stage fluctuations and associated hydroperiods and depths on the adjacent floodplain. Although prescribed changes to headwater inflows have not been fully implemented, substantial modifications of operational protocols were made to better resemble historical discharge regimes and thereby accommodate restoration during and following the initial reconstruction phase (Anderson 2014). ...
... Although delayed reestablishment of BLM is seemingly consistent with an "interim response period" , primary impediments (i.e. invasive species and altered soil characteristics) are independent of complete implementation of the headwaters revitalization component, which is the remaining limitation for reestablishing hydrology as a driver for full restoration of the Kissimmee River ecosystem (Anderson 2014). Moreover, the rampant colonization and spread of H. altissima, H. amplexicaulis, and U. mutica suggests that the invasion of these exotic grass species could represent an alternative stable state (Holling 1973;Beisner et al. 2003;Kulmatiski 2006) for the restored floodplain. ...
Restoration efforts are typically based on an assumption that reestablishment of altered determinants of ecological structure and function will lead to a predictable reestablishment of populations and reassembly of communities. Dechannelization and reestablishment of natural hydrologic regimes provide the basis for the ongoing restoration of the Kissimmee River in Central Florida, United States. The expected reestablishment of historically dominant broadleaf marsh (BLM) and buttonbush shrub (BB) communities was evaluated over a 10-year period following implementation of the first phase of the restoration project. Plant species composition and cover were assessed during dry (spring) and wet (summer) season sampling periods at five sites on the restored floodplain, and four “control” sites on the channelized floodplain. Mean daily stage data from nearby gauges indicated hydroperiods and depths on the reflooded floodplain were within the range of historic hydrologic conditions that selected for BLM and BB communities on the pre-channelization floodplain. After reflooding, pasture grass and upland shrub communities rapidly transitioned to a fluid mix of obligate and facultative wetland species. Although signature BLM and BB species, Sagittaria lancifolia (bulltongue arrowhead), Pontederia cordata (pickerel weed), and Cephalanthus occidentalis (buttonbush), recolonized all study sites, the expected reestablishment of dominant cover of these species did not occur. Results indicate that restoration of BLM and BB communities has been impeded by deep flood pulse disturbances, establishment of invasive wetland grasses, and mineralized soil characteristics of the drained floodplain.
... Establishing more natural drainage and vegeta-tion patterns is expected to further increase hydraulic, sediment and nutrient residence times and enhance the opportunity for landscape mitigation of terrestrial pollutant fluxes (Walling & Fang, 2003;Burt & Pinay, 2005;Mclellan et al., 2015). For example, restoration of the Kissimmee River in Florida, USA, resulted in hydrological processes recovering towards prechannelization conditions within 10 years (Anderson, 2014). The restoration or creation of wetlands (Verhoeven et al., 2006) and riparian zones (Tomer & Locke, 2011) can result in full recovery of nitrogen storage and cycling processes within 25-30 years (Moreno-Mateos et al., 2012), while restoration of native seagrass (Mcglathery et al., 2012) or oyster beds (Schulte et al., 2009) is likely to contribute to deposition and retention of suspended sediment, nutrient cycling and water filtration (Cloern, 2001;Mcglathery et al., 2012) and may significantly reduce concentrations in receiving waters (Cerco & Noel, 2010). ...
The Great Barrier Reef (GBR) is an iconic coral reef system extending over 2,000 km along the north-east coast of Australia. Global recognition of its Outstanding Universal Value resulted in the listing of the 348,000 km(2) GBR World Heritage Area (WHA) by UNESCO in 1981. Despite various levels of national and international protection, the condition of GBR ecosystems has deteriorated over the past decades, with land-based pollution from the adjacent catchments being a major, and ongoing cause for this decline. To reduce land-based pollution, the Australian and Queensland Governments have implemented a range of policy initiatives since 2003. Here, we evaluate the effectiveness of existing initiatives to reduce discharge of land-based pollutants into the waters of the GBR. We conclude that recent efforts in the GBR catchments to reduce land-based pollution are unlikely to be sufficient to protect the GBR ecosystems from declining water quality within the aspired timeframes. To support management decisions for desired ecological outcomes for the GBR WHA, we identify potential improvements to current policies and incentives, as well as potential changes to current agricultural land use, based on overseas experiences and Australia's unique potential. The experience in the GBR may provide useful guidance for the management of other marine ecosystems, as reducing land-based pollution by better managing agricultural sources is a challenge for coastal communities around the world. This article is protected by copyright. All rights reserved.
... The Kissimmee River Restoration Project was authorized by the Water Resources Development Act in 1992 and started in 1999 to restore wetland cover in the KRB [USACE, 1991;Dahm et al., 1995;Anderson, 2014], funded by both South Florida Water Management District (SFWMD) and the USACE [Department of the Army and SFWMD, 1994]. To date, more than half of the project (Phases I, IVa and IVb) has been completed [Koebel and Bousquin, 2014]. ...
The Kissimmee River Basin (Florida, USA) underwent river channelization in the 1960s and subsequent restoration in the 1990s, revealing a shift in management emphasis from flood protection to wetland health. In this paper this shift is hypothesized to result from changing human values and preferences, and a power differential between the more numerous and affluent upstream urban residents (who prioritize wetland restoration) and downstream rural residents (who prioritize flood protection). We develop a conceptual socio-hydrologic model to simulate the interactions between community interests and hydrology. The modeling results show that flood intensity decreased after channelization, which reduced concern about flooding. However, channelization also led to a decrease in wetland storage, which caused an increase of wetland concern, especially amongst the urban residents. Eventually, the community sensitivity switched from favoring flood protection to favoring wetlands, and subsequent management strategies switched from channelization to restoration. Using the model we project that the wetlands will be recovering for the next 20 years and community sensitivity will slowly go back to a neutral state. However, possible rainfall intensification in the future could return the community sensitivity to favoring flood protection again. The preferential increase of upstream population growth will raise the community's concern about wetlands and the preferential increase of downstream population growth will magnify concern about flooding. This study provides insight into the driving forces behind human-water interactions in the Kissimmee River Basin while simultaneously demonstrating the potential of socio-hydrologic modeling to describe complex human-water coupled systems with simple concepts and equations.
Measurements of littoral vegetation stands and species-level surveys of associated plant communities were made in channels of the Kissimmee River from 1998 through 2008, a period that spanned channelized, non-flowing conditions through 7 years of near-continuous reestablished flow. Dissected by flood control canal C-38 in 1971, the river was virtually without flow until early 2001, when Phase I of the Kissimmee River Restoration Project (KRRP) reestablished flow to a central section of river channel. This study evaluated the effects of reestablished flow on littoral vegetation in river channels as an indicator of system status and progress toward the project goal of ecological integrity. Predictions of vegetation response to reestablished flow included reduction in the width of vegetation stands, and changes in the growth-form composition of littoral stands from near-equal dominance by floating and emergent species to overwhelming dominance by emergent growth forms. Variables included plant cover by species and growth-form, width of vegetation stands, and vegetated percentage of channel. Under the currently incomplete (interim) status of the KRRP, results for littoral vegetation stands indicate trends in the predicted directions of change, and three of four predicted changes have occurred. Vegetation stand widths decreased substantially and littoral plant communities became heavily dominated by emergent species; BACIPS (before-after-control-impact-paired series) analyses indicated significant restoration effects for most littoral stand metrics.
Channelization of the Kissimmee River eliminated flow through the river channel, which allowed the formation of a largely organic deposition layer (ODL) on the river channel bed and stopped active sand transport needed to maintain point bars on meander bends. In 2001, completion of the first phase of dechannelization for the Kissimmee River Restoration Project (KRRP) reestablished flow to the river channel in the Phase I area. This study evaluated changes in the ODL and the number of meander bends with active point bar development (MBPB) following Phase I of dechannelization. Evaluations involved comparing interim measurements made after flow was reestablished to the river channel in the Phase I area but before full completion of KRRP with (a) baseline measurements made before dechannelization and (b) predicted changes based on reference measurements representing the pre-channelization system. ODL thickness was measured in core samples on fixed transects perpendicular to the river channel. The ODL was thinner during the Interim Period than the Baseline Period and this decrease exceeded the expected change predicted from the reference condition. MBPB was assessed with aerial photography. MBPB increased from the baseline measurement of 0 bends to interim measurements of 27 bends in 2002 and 72 bends in 2009, approximating the increase predicted from the reference condition. The decrease in ODL thickness and the increase in MBPB to levels that meet or approximate the reference condition indicate that these aspects of the river channel are recovering following reestablishment of flow.
Over the past decade, restoration of the Kissimmee River in central Florida has received considerable attention from local, state, national, and international media. In terms of areal extent, project cost, and ecological evaluation it is one of the largest and most comprehensive river restoration projects in the world. The goal of reestablishing ecological integrity involves restoring the physical attributes and the hydrologic processes that were lost after channelization of the river in the 1960s. The project is expected to restore over 80 km2 of floodplain wetlands and reestablish over 70 km of river channel. Restoration construction began in 1999; to date, three construction phases have been completed, with the final phase of construction slated for completion in 2019. Restoration evaluation is widely viewed as a critical component of any restoration project. Equally important is the dissemination of information gained from restoration evaluation programs. This introductory article presents a brief overview of project history and outlines the approach and logic of the Kissimmee River Restoration Evaluation Program. The following papers present the results of ecological studies conducted before and after completion of the first phase of restoration construction. This first phase reestablished flow through 23 km of reconnected river channels and seasonally inundated a large portion (approximately 2,900 ha) of the floodplain within the Phase I project area. Although these studies present interim responses prior to full hydrologic restoration, results suggest that the ecosystem is responding largely as predicted by performance measures developed prior to restoration construction.
River damming has dramatic environmental impacts and while changes due to reservoir flooding are immediate, downstream impacts are more spatially extensive. Downstream environments are influenced by the pattern of flow regulation, which also provides an opportunity for mitigation. We discuss impacts downstream from dams and recent case studies where collaborative efforts with dam operators have led to the recovery of more natural flow regimes. These restoration programs, in Nevada, USA, and Alberta, Canada, focused on the recovery of flow patterns during high flow years, because these are critical for riparian vegetation and sufficient water is available for both economic commitments and environmental needs. The restoration flows were developed using the "Recruitment Box Model", which recommends high spring flows and then gradual flow decline for seedling survival. These flow regimes enabled extensive recruitment of cottonwoods and willows along previously impoverished reaches, and resulted in improvements to river and floodplain environments. Such restoration successes demonstrate how instream flow management can act as a broadly applicable tool for the restoration of floodplain forests.
Major controls on the retention, distribution, and discharge of surface water in the historic (precanal) Kissimmee drainage basin and river were investigated to determine reference conditions for ecosystem restoration. Precanal Kissimmee drainage-basin hydrology was largely controlled by landforms derived from relict, coastal ridge, lagoon, and shallow-shelf features; widespread carbonate solution depressions; and a poorly developed fluvial drainage network. Prior to channelization for flood control, the Kissimmee River was a very low gradient, moderately meandering river that flowed from Lake Kissimmee to Lake Okeechobee through the lower drainage basin. We infer that during normal wet seasons, river discharge rapidly exceeded Lake Okeechobee outflow capacity, and excess surface water backed up into the low-gradient Kissimmee River. This backwater effect induced bankfull and peak discharge early in the flood cycle and transformed the flood plain into a shallow aquatic system with both lacustrine and riverine characteristics. The large volumes of surface water retained in the lakes and wetlands of the upper basin maintained overbank flow conditions for several months after peak discharge. Analysis indicates that most of the geomorphic work on the channel and flood plain occurred during the frequently recurring extended periods of overbank discharge and that discharge volume may have been significant in determining channel dimensions. Comparison of hydrogeomorphic relationships with other river systems identified links between geomorphology and hydrology of the precanal Kissimmee River. However, drainage-basin and hydraulic geometry models derived solely from general populations of river systems may produce spurious reference conditions for restoration design criteria.
The 1996 controlled flood released from Glen Canyon Dam into the Colorado River was a small magnitude, short duration event compared to pre-dam floods. The con- trolled flood was of lesser magnitude than a 1.25-yr recurrence, and only 10% of the pre- dam spring snowmelt floods during the period 1922-1962 were of lower magnitude. The flood occurred unusually early: 36-38 d prior to any previous annual flood since 1922. The stage difference between the flood's peak and the recessional baseflow was smaller than in those pre-dam years of similar magnitude or annual volume. However, the controlled flood was large from the perspective of the post-dam flood regime. The flood had a recurrence of 5.1 yr for the period between 1963 and 1999 and a similar magnitude flood had not occurred in 10 yr. The sediment flux of the flood was small in relation to pre-dam floods, and the suspended sand concentration was within the historical variance for flows of similar magnitude. This flood reworked fine-grained deposits that are primarily composed of sand, but the flood caused much less reworking of coarser grained deposits. Scour primarily occurred in the offshore parts of eddies, in many eddy return-current channels, and in some parts of the main channel. Return-current channels constitute important nursery habitats for the native fishery when baseflows are low, because these channels become areas of stagnant and warmer water. The number and area of these backwaters increased greatly after the flood. Fluvial marshes were extensively scoured because these habitats occur in the low elevation centers of eddies where velocities during the flood were large. Riparian shrubs that were inundated along the banks were not scoured, however, because these shrubs occur where flood velocities were very low and where deposition of suspended sediment occurred. Some physical changes persisted for several years, but other changes, such as the area of newly formed backwaters decreased quickly. Thus, the lasting effect of this flood varied among different small-scale fluvial environments.
The ongoing restoration of the channelized Kissimmee River is expected to promote reestablishment of the prolonged, deep inundation regimes that sustained broadleaf marsh as the dominant wetland plant community on the historical floodplain. The success of the restoration was evaluated at locations on the remnant floodplain where broadleaf marsh had been replaced by a mesophytic shrub community, and on the lower portion of the reconstructed floodplain, which was recreated by backfilling of a flood control canal and degradation of associated spoil mounds. During the 8-year post-restoration period (2001–2008) mean annual hydroperiods and depths on the restored floodplain were not significantly different from pre-channelization hydrologic conditions at historical reference sites. Increased hydroperiods and depths eliminated the mesophytic shrub (primarily Myrica cerifera) and associated fern cover, and led to colonization of floating and mat-forming species, but did not result in the reestablishment of a broadleaf marsh community. Signature broadleaf marsh species, Sagittaria lancifolia and Pontederia cordata, were found in all remnant floodplain plots and colonized 8 of the 10 reconstructed floodplain plots, but had mean cover ranging from only 0.9 to 6.1%. Several factors may have contributed to unsuccessful reestablishment of broadleaf marsh, including unfavorable edaphic conditions, brief drawdown (low stage) periods for establishment of seedlings, flood induced mortality, and an invasion of the exotic shrub, Ludwigia peruviana, which had post-restoration mean cover of 17–19%. Study results indicate hydrologic restoration of floodplain plant communities can be influenced by more discrete aspects of the river flood pulse than average hydroperiods and depths.
1] Reengineering of stream channels is a common approach used to restore hydrologic function in degraded landscapes, but there has been little published research analyzing its effectiveness. A key challenge for impact assessment is disentangling the effects of restoration from climate variability. Trout Creek, near Lake Tahoe, California, was reengineered to reestablish hydrologic connectivity between the stream and its former floodplain. Gauges located above and below the site, along with groundwater well measurements, were used to analyze prerestoration and postrestoration hydrology. Results show that restoration has a seasonal impact with statistically significant increases in streamflow during the summer recession period and decreased groundwater table depths across a wide range of streamflow conditions. Paired gauges and statistical models that are robust to serial autocorrelation demonstrate a feasible approach for assessing hydrologic restoration in regions where climate patterns lead to substantial within-year and between-years variation in streamflow.
The term flashiness reflects the frequency and rapidity of short term changes in streamflow, especially during runoff events. Flashiness is an important component of a stream's hydrologic regime. A variety of land use and land management changes may lead to increased or decreased flashiness, often to the detriment of aquatic life. This paper presents a newly developed flashiness index, which is based on mean daily flows. The index is calculated by dividing the pathlength of flow oscillations for a time interval (i.e., the sum of the absolute values of day-to-day changes in mean daily flow) by total discharge during that time interval. This index has low interannual variability, relative to most flow regime indicators, and thus greater power to detect trends. Index values were calculated for 515 Midwestern streams for the 27-year period from 1975 through 2001. Statistically significant increases were present in 22 percent of the streams, primarily in the eastern portion of the study area, while decreases were present in 9 percent, primarily in the western portion. Index values tend to decrease with increasing watershed area and with increasing unit area ground water inputs. Area compensated index values often shift at ecoregion boundaries. Potential index applications include evaluation of programs to restore more natural flow regimes.
Broadleaf marsh once covered much of the wetland landscape along the Kissimmee River in central Florida, USA, but is currently
restricted to remnant portions of the channelized floodplain that have been subjected to much shallower depths. The initial
phase of Kissimmee River restoration, which began in 1999, and a prior (1984–1990) demonstration project increased water depths
in several relict broadleaf marshes on the floodplain. Effects of restored water depth regimes on characteristics of these
altered broadleaf marsh communities were evaluated. As expected, plant species richness consistently declined in marshes with
increased water depth, but cover of signature broadleaf species, Sagittaria lancifolia and Pontederia cordata, exhibited variable responses to restored hydrology. In one marsh mean cover of Sagittaria and Pontederia increased from 32 to 62% following a 37cm increase in mean annual depths; however, in another relict marsh that underwent
a similar increase in hydroperiods and depths, mean cover of these species remained below 30% and Panicum hemitomon persisted as a dominant species. Moreover, invasion of the exotic wetland shrub, Ludwigia peruviana, appears to pose a threat to successful restoration of broadleaf marshes on the Kissimmee floodplain.
Keywords
Ludwigia peruviana
-Kissimmee River-Wetland restoration
"The construction of new dams has become one of the most controversial issues in global efforts to alleviate poverty, improve human health, and strengthen regional economies. Unfortunately, this controversy has overshadowed the tremendous opportunity that exists for modifying the operations of existing dams to recover many of the environmental and social benefits of healthy ecosystems that have been compromised by present modes of dam operation. The potential benefits of dam re-operation include recovery of fish, shellfish, and other wildlife populations valued both commercially and recreationally, including estuarine species; reactivation of the flood storage and water purification benefits that occur when floods are allowed to flow into floodplain forests and wetlands; regaining some semblance of the naturally dynamic balance between river erosion and sedimentation that shapes physical habitat complexity, and arresting problems associated with geomorphic imbalances; cultural and spiritual uses of rivers; and many other socially valued products and services. This paper describes an assessment framework that can be used to evaluate the benefits that might be restored through dam re-operation. Assessing the potential benefits of dam re-operation begins by characterizing the dams effects on the river flow regime, and formulating hypotheses about the ecological and social benefits that might be restored by releasing water from the dam in a manner that more closely resembles natural flow patterns. These hypotheses can be tested by implementing a re-operation plan, tracking the response of the ecosystem, and continually refining dam operations through adaptive management. The paper highlights a number of land and water management strategies useful in implementing a dam re-operation plan, with reference to a variety of management contexts ranging from individual dams to cascades of dams along a river to regional energy grids. Because many of the suggested strategies for dam re-operation are predicated on changes in the end-use of the water, such as reductions in urban or agricultural water use during droughts, a systemic perspective of entire water management systems will be required to attain the fullest possible benefits of dam re-operations."
Phase I of the Kissimmee River Restoration Project
(KRRP) reestablished intermittent inundation of the
river’s floodplain by backfilling 12 km of the C-38 flood
control canal in 2001. We compared floodplain vegetation
maps based on 2003 and 2008 aerial imagery (2 and 7 years
following completion of Phase I, respectively) to vegetation
maps from 1954 (pre-channelization), 1974 (3 years
after channelization), and 1996 (25 years after channelization)
to evaluate broad-scale vegetation responses to
Phase I restoration. Results indicate that the extent of
wetland plant communities expanded rapidly, more than
doubling in area within 2 years after completion of Phase
I, and that by 2008 wetlands had nearly recovered to
pre-channelization levels. However, full reestablishment
of the pre-channelization wetland mosaic has not yet
occurred. Prior to channelization, much of the floodplain
was dominated by a broadleaf marsh (BLM) community
associated with extended, deep annual flooding, while
shorter-hydroperiod communities dominated the floodplain
in 2003 and 2008. Prior to restoration construction,
the reestablishment of BLM was predicted to be slow
because suitable hydrology is dependent on project components
that will not be in place until all restoration
components are completed (projected for 2019). Hydrologic
data indicate that the duration and variability of
floodplain inundation have not yet achieved restoration
targets over the entire Phase I study area. Other factors
affecting vegetation responses are likely involved,
including the age and viability of soil seed banks, the rarity
of relict propagule sources following the channelized
period, and competition from an invasive wetland shrub
species.
Key words: hydroperiod restoration, marsh, restoration
evaluation, vegetation mapping, wet prairie, wetlands.
Measurements of littoral vegetation stands and species-level surveys of associated plant communities were made in channels of the Kissimmee River from 1998 through 2008, a period that spanned channelized, non-flowing conditions through 7 years of near-continuous reestablished flow. Dissected by flood control canal C-38 in 1971, the river was virtually without flow until early 2001, when Phase I of the Kissimmee River Restoration Project (KRRP) reestablished flow to a central section of river channel. This study evaluated the effects of reestablished flow on littoral vegetation in river channels as an indicator of system status and progress toward the project goal of ecological integrity. Predictions of vegetation response to reestablished flow included reduction in the width of vegetation stands, and changes in the growth-form composition of littoral stands from near-equal dominance by floating and emergent species to overwhelming dominance by emergent growth forms. Variables included plant cover by species and growth-form, width of vegetation stands, and vegetated percentage of channel. Under the currently incomplete (interim) status of the KRRP, results for littoral vegetation stands indicate trends in the predicted directions of change, and three of four predicted changes have occurred. Vegetation stand widths decreased substantially and littoral plant communities became heavily dominated by emergent species; BACIPS (before-after-control-impact-paired series) analyses indicated significant restoration effects for most littoral stand metrics.
Channelization of the Kissimmee River eliminated flow through the river channel, which allowed the formation of a largely organic deposition layer (ODL) on the river channel bed and stopped active sand transport needed to maintain point bars on meander bends. In 2001, completion of the first phase of dechannelization for the Kissimmee River Restoration Project (KRRP) reestablished flow to the river channel in the Phase I area. This study evaluated changes in the ODL and the number of meander bends with active point bar development (MBPB) following Phase I of dechannelization. Evaluations involved comparing interim measurements made after flow was reestablished to the river channel in the Phase I area but before full completion of KRRP with (a) baseline measurements made before dechannelization and (b) predicted changes based on reference measurements representing the pre-channelization system. ODL thickness was measured in core samples on fixed transects perpendicular to the river channel. The ODL was thinner during the Interim Period than the Baseline Period and this decrease exceeded the expected change predicted from the reference condition. MBPB was assessed with aerial photography. MBPB increased from the baseline measurement of 0 bends to interim measurements of 27 bends in 2002 and 72 bends in 2009, approximating the increase predicted from the reference condition. The decrease in ODL thickness and the increase in MBPB to levels that meet or approximate the reference condition indicate that these aspects of the river channel are recovering following reestablishment of flow.
Over the past decade, restoration of the Kissimmee River in central Florida has received considerable attention from local, state, national, and international media. In terms of areal extent, project cost, and ecological evaluation it is one of the largest and most comprehensive river restoration projects in the world. The goal of reestablishing ecological integrity involves restoring the physical attributes and the hydrologic processes that were lost after channelization of the river in the 1960s. The project is expected to restore over 80 km2 of floodplain wetlands and reestablish over 70 km of river channel. Restoration construction began in 1999; to date, three construction phases have been completed, with the final phase of construction slated for completion in 2019. Restoration evaluation is widely viewed as a critical component of any restoration project. Equally important is the dissemination of information gained from restoration evaluation programs. This introductory article presents a brief overview of project history and outlines the approach and logic of the Kissimmee River Restoration Evaluation Program. The following papers present the results of ecological studies conducted before and after completion of the first phase of restoration construction. This first phase reestablished flow through 23 km of reconnected river channels and seasonally inundated a large portion (approximately 2,900 ha) of the floodplain within the Phase I project area. Although these studies present interim responses prior to full hydrologic restoration, results suggest that the ecosystem is responding largely as predicted by performance measures developed prior to restoration construction.
The Tennessee Valley Authority (TVA) initiated a Reservoir Releases Improvement Program in 1991 to increase minimum flows and improve water quality by modifying its dam operations. We compiled a comprehensive data set from ecological monitoring below nine dams to evaluate the effects of these modifications on physicochemical conditions and benthic macroinvertebrate assemblages. Abiotic and biotic data were collected in tailwaters by the TVA for three dam operation "treatments" (i.e., before any modifications, following flow modifications, and following both flow and dissolved oxygen [DO] modifications) at three different stations (Upper, Middle, and Lower) located at increasing longitudinal distances below each dam. Analysis of variance was used to test for differences in ecological conditions among treatments and stations. Dam modifications had significant effects on both abiotic and biotic variables, and macroinvertebrate assemblages exhibited significant longitudinal differences. Yearly mean DO and mean minimum velocity increased following dam modifications. Across all sampling stations, macroinvertebrate family richness increased and the percentage of pollution-tolerant macroinvertebrates (% Tolerant) decreased after dam modifications. Family richness also increased, and % Tolerant decreased, with increasing distance below the dams. Total abundance of macroinvertebrates increased after flow modifications and then decreased following changes in DO. The percentage of individuals belonging to the orders Ephemeroptera, Plecoptera, and Trichoptera (% EPT) increased following flow and DO modifications, but only at the Upper station. EPT family richness was unaffected by increased flow alone but increased following increases in both flow and DO. The design of the reoperation "experiment" made it difficult to ascertain the relative contributions of flow and DO changes to the observed biotic responses, but flow alone appeared to have a smaller beneficial effect than the combined effects of flow and DO.
As an inevitable consequence of increased environmental degradation and anticipated future environmental change, societal demand for ecosystem restoration is rapidly increasing. Here, I evaluate successes and failures in restoration, how science is informing these efforts, and ways to better address decision-making and policy needs. Despite the multitude of restoration projects and wide agreement that evaluation is a key to future progress, comprehensive evaluations are rare. Based on the limited available information, restoration outcomes vary widely. Cases of complete recovery are frequently characterized by the persistence of species and abiotic processes that permit natural regeneration. Incomplete recovery is often attributed to a mixture of local and landscape constraints, including shifts in species distributions and legacies of past land use. Lastly, strong species feedbacks and regional shifts in species pools and climate can result in little to no recovery. More forward-looking paradigms, such a...
1] Interrelationships between hydrology and aquatic ecosystems are better understood in streams and rivers compared to their surrounding floodplains. Our goal was to characterize the hydrology of the Everglades ridge and slough floodplain ecosystem, which is valued for the comparatively high biodiversity and connectivity of its parallel-drainage features but which has been degraded over the past century in response to flow reductions associated with flood control. We measured flow velocity, water depth, and wind velocity continuously for 3 years in an area of the Everglades with well-preserved parallel-drainage features (i.e., 200-m wide sloughs interspersed with slightly higher elevation and more densely vegetated ridges). Mean daily flow velocity averaged 0.32 cm s À1 and ranged between 0.02 and 0.79 cm s À1 . Highest sustained velocities were associated with flow pulses caused by water releases from upstream hydraulic control structures that increased flow velocity by a factor of 2–3 on the floodplain for weeks at a time. The highest instantaneous measurements of flow velocity were associated with the passage of Hurricane Wilma in 2005 when the inverse barometric pressure effect increased flow velocity up to 5 cm s À1 for several hours. Time-averaged flow velocities were 29% greater in sloughs compared to ridges because of marginally higher vegetative drag in ridges compared to sloughs, which contributed modestly (relative to greater water depth and flow duration in sloughs compared to ridges) to the predominant fraction (86%) of total discharge through the landscape occurring in sloughs. Univariate scaling relationships developed from theory of flow through vegetation, and our field data indicated that flow velocity increases with the square of water surface slope and the fourth power of stem diameter, decreases in direct proportion with increasing frontal area of vegetation, and is unrelated to water depth except for the influence that water depth has in controlling the submergence height of vegetation that varies vertically in its architectural characteristics. In the Everglades the result of interactions among controlling variables was that flow velocity was dominantly controlled by water surface slope variations responding to flow pulses more than spatial variation in vegetation characteristics or fluctuating water depth. Our findings indicate that floodplain managers could, in addition to managing water depth, manipulate the frequency and duration of inflow pulses to manage water surface slope, which would add further control over flow velocities, water residence times, sediment settling, biogeochemical transformations, and other processes that are important to floodplain function.
The need for effective marsh restoration techniques in Louisiana is a pressing issue as the state continues to lose coastal wetlands. Returning spoil banks to canals, known as “backfilling,” is an attractive restoration option because it restores marsh, prevents future wetland loss, and is cost effective. The restoration of 30 canals backfilled 20 years ago was examined in this study and compared to restoration success 5 and 10 years after backfilling. Ultimately, the success of backfilling was controlled by the amount of spoil returned to the canal and the position of the canal in the marsh. Up to 95% of the spoil area was restored to marsh when the spoil banks were adequately removed, but only 5% of the spoil area was restored at sites where spoil removal was poor. Restoration of organic matter, bulk density, water content, and plant communities of the former spoil areas was also constrained by the adequacy of spoil removal. Backfilling restored up to 90% of the organic matter, 92% of the bulk density, and 93% of the water content after 20 years at sites where spoil was properly removed. Canals backfilled in areas of intact marsh showed greater restoration success than canals backfilled in highly degraded marshes. This study indicates that the benefits of backfilling continue to increase over time, although complete restoration will take longer than 20 years. Improving the completeness of spoil removal, coupled with appropriate site selection, could speed up the restoration process and enhance the success of future backfilling projects.
This paper presents the results of a study on the use of continuous stage data to describe the relation between urban development and three aspects of hydrologic condition that are thought to influence stream ecosystems—overall stage variability, stream flashiness, and the duration of extreme-stage conditions. This relation is examined using data from more than 70 watersheds in three contrasting environmental settings—the humid Northeast (the metropolitan Boston, Massachusetts, area); the very humid Southeast (the metropolitan Birmingham, Alabama, area); and the semiarid West (the metropolitan Salt Lake City, Utah, area). Results from the Birmingham and Boston studies provide evidence linking increased urbanization with stream flashiness. Fragmentation of developed land cover patches appears to ameliorate the effects of urbanization on overall variability and flashiness. There was less success in relating urbanization and streamflow conditions in the Salt Lake City study. A related investigation of six North Carolina sites with long term discharge and stage data indicated that hydrologic condition metrics developed using continuous stage data are comparable to flow based metrics, particularly for stream flashiness measures.
Although public and financial support for stream restoration projects is increasing, long-term monitoring and reporting of project successes and failures are limited. We present the initial results of a long-term monitoring program for the Lower Red River Meadow Restoration Project in north-central Idaho, U.S.A. We evaluate a natural channel design’s effectiveness in shifting a degraded stream ecosystem onto a path of ecological recovery. Field monitoring and hydrodynamic modeling are used to quantify post-restoration changes in 17 physical and biological performance indicators. Statistical and ecological significance are evaluated within a framework of clear objectives, expected responses (ecological hypotheses), and performance criteria (reference conditions) to assess post-restoration changes away from pre-restoration conditions. Compared to pre-restoration conditions, we observed ecosystem improvements in channel sinuosity, slope, depth, and water surface elevation; quantity, quality, and diversity of in-stream habitat and spawning substrate; and bird population numbers and diversity. Modeling documented the potential for enhanced river–floodplain connectivity. Failure to detect either statistically or ecologically significant change in groundwater depth, stream temperature, native riparian cover, and salmonid density is due to a combination of small sample sizes, high interannual variability, external influences, and the early stages of recovery. Unexpected decreases in native riparian cover led to implementation of adaptive management strategies. Challenges included those common to most project-level monitoring—isolating restoration effects in complex ecosystems, securing long-term funding, and implementing scientifically rigorous experimental designs. Continued monitoring and adaptive management that support the establishment of mature and dense riparian shrub communities are crucial to overall success of the project.
Since 1857 new Australians have constructed many thousands of weirs (3600 in the Murray-Darling Basin alone) and floodplain levee banks, 446 large dams (>10 m crest height) and over 50 intra- and inter-basin water transfer schemes to secure water supplies for human use. Flow regulation has changed the hydrology of major rivers on three temporal sales-the flood pulse (days to weeks), flow history (weeks to years) and the long-term statistical pattern of flows, or flow regime (decades or longer). The regulation of river flows is widely acknowledged as a major cause of deteriorating conditions in many Australian river and floodplain ecosystems. In response to mounting environmental concerns, all states, territories and the Commonwealth Government have committed the nation to the principles of ecologically sustainable development and a process of national water reform. Rivers and wetlands are now recognized as legitimate users of water, and jurisdictions must provide water allocations to sustain and where necessary restore ecological processes and the biodiversity of water-dependent ecosystems. Progress in the protection and restoration of river and wetland water regimes has been significant, with over half of mainland aquatic systems designated to receive water allocations of some sort. However, exactly how much water they will receive or retain is unclear from the data available. Moreover, the ecological outcomes and benefits of water allocations are not yet apparent in most aquatic ecosystems, with the exception of certain waterbird breeding events, the disruption of algal blooms in weirs and improved fish passage. After reviewing these issues, this paper addresses two vital questions: How much water does a river need? and How can this water be clawed back from other users? Studies conducted to date in Queensland rivers suggest that around 80-92% of natural mean annual flow (and other ecologically relevant hydrological indicators) may be needed to maintain a low risk of environmental degradation. In the Top End of the Northern Territory, some rivers are maintained at 80% of their natural flow, whereas two-thirds of various flow indicators has been proposed as the restoration target for the River Murray, and 28% of natural mean annual flow has been negotiated for the Snowy River in Victoria. To validate these estimates, ecologists are seeking opportunities to turn river restoration projects into long-term hypothesis-driven experiments in ecological restoration, and the funding, time and institutional support to do so. The paper ends with some suggestions to advance the water reforms and achieve higher levels of water allocation for the environment. Yes Yes
This paper is a test of two widely held assumptions in the practice of riparian restoration: (1) if physical processes are restored, plant communities will naturally reassemble themselves, and (2) restored communities will resemble reference sites. Seasonal flooding was restored to two interconnected floodplains in the Central Valley of California (USA), and plant community establishment was studied for six years at 300 permanent vegetation plots. If these two assumptions are valid, then the two floodplains should end up with similar plant assemblages, and they should both have followed a similar trajectory. Then, once the relevant physical processes are restored, (1) plots with similar environmental conditions should have increasingly similar species compositions, (2) plant communities should become more stable and cohesive, (3) both species distributions and plant communities should respond to changes in environmental conditions, (4) plot diversity should decrease, and (5) perennial species should replace annuals. The plots were classified into communities using TWINSPAN, and these communities differed significantly with respect to the main environmental gradient (inundation). Bray-Curtis similarities were calculated for each pair of plots. Patterns in similarity were used to test the strength of communities and the relative importance of proximity and inundation. On the northern floodplain, there was a trend of increasing similarity for plots with similar environmental conditions over the course of the study; plant communities became more stable and clearly responded to changes in environmental conditions. Plot diversity decreased, and the proportion of perennial species increased. On the southern floodplain, however, plots with similar environmental conditions became less similar, while plots that were close together became more similar; plant communities did not become more stable though they did shift in response to changes in environmental conditions. Taken together, this evidence suggests that assembly of communities is more stochastic than deterministic.
A conceptual basis for evaluating restoration success
- D H Anderson
- B D Dugger
Anderson, D. H., and B. D. Dugger. 1998. A conceptual basis for evaluating restoration success. Transactions of the North American Wildlife and Natural Resources Conference 63:111–121.
Drainage-basin-scale geomorphic analysis to determine reference conditions for ecological restoration - Kissimmee River, Florida
- Warne
Defining success: expectations for restoration of the Kissimmee River. South Florida Water Management District West Palm Beach Florida
- D H S G Anderson
- G E Bousquin
- Williams