Forested wetlands for water resource management in southern Illinois

A 30 ha cypress - tupelo (Taxodium distichum - Nyssa aquatics), floodplain swamp in Southern Illinois was studied for its hydrologic, biogeochemical and ecological characteristics. The hydrology, water chemistry, sediment dynamics and ecosystem productivity were described for the swamp and interactions with the adjacent Cache River were emphasized. A representative flood in the spring spilled water and sediments from the river to the swamp, temporarily reversing the normal flow of water from the swamp to the river. The annual hydrology budget for the swamp showed inflows of 7'4.4 cm throughfall, 63.9 cm runoff, and 21.9 cm groundwater; the outflows were 7'2.8 cm evapotranspiration, 54.9 cm surface outflow, and 21.0 cm groundwater, the latter two draining to the river. Loading rates for several chemical parameters were calculated from the swamp to the river and water chemistry of the swamp and river was contrasted. Primary productivity measurements showed high rates when the floating duckweed was included; cypress productivity was shown historically to be related to amount of flooding. A phosphorus budget was determined for the swamp and this indicated that the flooding river contributed over 10 times the phosphorus to the swamp as was discharged the rest of the year.U.S. Department of the InteriorU.S. Geological SurveyOpe

Estimation and comparison of gross primary productivity patterns in created riparian wetlands

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Potential for long-term transfer of dissolved organic carbon from riparian zones to streams in boreal catchments

Boreal regions store most of the global terrestrial carbon, which can be transferred as dissolved organic carbon (DOC) to inland waters with implications for both aquatic ecology and carbon budgets. Headwater riparian zones (RZ) are important sources of DOC, and often just a narrow ‘dominant source layer' (DSL) within the riparian profile is responsible for most of the DOC export. Two important questions arise: how long boreal RZ could sustain lateral DOC fluxes as the sole source of exported carbon and how its hydromorphological variability influences this role. We estimate theoretical turnover times by comparing carbon pools and lateral exports in the DSL of 13 riparian profiles distributed over a 69km2 catchment in northern Sweden. The thickness of the DSL was 36±18 (average ± SD) cm. Thus, only about one-third of the 1-m-deep riparian profile contributed 90% of the lateral DOC flux. The 13 RZ exported 8.7±6.5g C m-2year-1, covering the whole range of boreal stream DOC exports. The variation could be explained by local hydromorphological characteristics including RZ width (R2=0.90). The estimated theoretical turnover times were hundreds to a few thousands of years, that is there is a potential long-lasting supply of DOC. Estimates of net ecosystem production in the RZ suggest that lateral fluxes, including both organic and inorganic C, could be maintained without drawing down the riparian pools. This was supported by measurements of stream DO14C that indicated modern carbon as the predominant fraction exported, including streams disturbed by ditching. The transfer of DOC into boreal inland waters from new and old carbon sources has a major influence on surface water quality and global carbon balances. This study highlights the importance of local variations in RZ hydromorphology and DSL extent for future DOC fluxes under a changing climate

Atlas of Wetlands in the Principal Coal Surface Mining Region of Western Kentucky

This atlas contains maps of wetlands and surface mining activity in the Western Kentucky Coal Field, and focuses on a 3960 km2 (1530 mi2) region where approximately 90 percent of surface mining in the Coal field occures. Some present and potential competition exists between surface coal mining and wetland protection. A wetland classification, based on the recent FWS classification, includes six types of palustrine systems and one each of riverine and laucstrine systems. Wetlands and surface mines are located on twenty-seven 7.5 minute USGS quadrangles that define the study region. A total of 460 km2 (177 mi2) of wetlands are identified. Approximately 84 percent are broad-leaved deciduous forested wetlands, mostly as periodically-flooded riparian hardwood forests along broad alluvial bottom-lands. Also, several significant persistent emergent wetlands, shrub-scrub wetlands, and needle-leaved deciduous forested wetlands (bald cypress swamps) are identified in the study region. Summaries of geology and coal mining, hydrology, water quality, wetland vegetation and unique fish and wildlife species are presented for each quadrangle. Effects of existing and potential future surface mining of coal on wetland structure, function, and value are discussed. Species lists for vegetation and fish and wildlife and recent water quality data for the study region are given in the Appendices

A New Simulation Metric to Determine Safe Environments and Controllers for Systems with Unknown Dynamics

We consider the problem of extracting safe environments and controllers for reach-avoid objectives for systems with known state and control spaces, but unknown dynamics. In a given environment, a common approach is to synthesize a controller from an abstraction or a model of the system (potentially learned from data). However, in many situations, the relationship between the dynamics of the model and the \textit{actual system} is not known; and hence it is difficult to provide safety guarantees for the system. In such cases, the Standard Simulation Metric (SSM), defined as the worst-case norm distance between the model and the system output trajectories, can be used to modify a reach-avoid specification for the system into a more stringent specification for the abstraction. Nevertheless, the obtained distance, and hence the modified specification, can be quite conservative. This limits the set of environments for which a safe controller can be obtained. We propose SPEC, a specification-centric simulation metric, which overcomes these limitations by computing the distance using only the trajectories that violate the specification for the system. We show that modifying a reach-avoid specification with SPEC allows us to synthesize a safe controller for a larger set of environments compared to SSM. We also propose a probabilistic method to compute SPEC for a general class of systems. Case studies using simulators for quadrotors and autonomous cars illustrate the advantages of the proposed metric for determining safe environment sets and controllers.Comment: 22nd ACM International Conference on Hybrid Systems: Computation and Control (2019