Since most wetlands in the Sacramento Valley of California are dependent on artificial water delivery, supplying water for wetland management is the greatest challenge to wetland managers, especially during drought years. Efforts are needed to improve the security of water supplies for optimal habitat management and water quality improvement. This study contributes to these efforts by developing an eco-hydrologic model (Agricultural Policy/Environmental Extender [APEX]) of this wetland system, which has key components evaluated in the wetland simulation, including wetting and drying of wetland soils, competition and response of wetland species to wetland hydrology, settling of sediment, and nitrogen (N) removal. APEX model calibration (April of 2017 to May of 2018) and validation (June of 2018 to August of 2018) resulted in a percentage bias (PB) of 9.8% and –8.5%, respectively, for total volume of water holding in four serially connected wetlands. The N contents in the wetland waterbody were calibrated and validated using the monitored values collected during 2017 to 2018 and 2015 to 2016, respectively. All PB values for calibration and validation were over 35%. The calibrated model was used to evaluate the effects of wetland management and increasing temperature on N removal. Moreover, an additive regression model (ARM) was developed based on bird survey data and used to analyze bird dropping seasonal patterns and access their impacts on water quality in the studied wetlands. Based on the results of the model, the wetland water quality was influenced by waterfowl populations and eventually governed by water availability in each wetland cell. The N removal by wetlands was negatively affected by the volume of irrigation water. Moreover, increasing temperature caused a decrease in waterfowl population, which led to decreased N concentration by up to 42%. Overall, the results indicate that the developed model can be effectively used to quantify the effects of wetland management on water balance, water quality, and vegetation and to describe the nexus of wetland management, water use, and ecosystem service functions of managed wetlands.

中文翻译：

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APEX 模拟：受水禽粪便影响的萨克拉门托河谷湿地水质

由于加利福尼亚州萨克拉门托河谷的大部分湿地都依赖于人工输水，因此为湿地管理供水是湿地管理者面临的最大挑战，尤其是在干旱年份。需要努力改善供水安全，以实现最佳栖息地管理和水质改善。本研究通过开发该湿地系统的生态水文模型（农业政策/环境扩展器 [APEX]）为这些努力做出贡献，该模型具有在湿地模拟中评估的关键组成部分，包括湿地土壤的润湿、竞争和响应湿地物种到湿地水文、沉积物沉降和氮 (N) 去除。APEX 模型校准（2017 年 4 月至 2018 年 5 月）和验证（2018 年 6 月至 2018 年 8 月）导致四个系列的总持水量的百分比偏差 (PB) 分别为 9.8% 和 –8.5%相连的湿地。分别使用2017-2018年和2015-2016年的监测值对湿地水体中的N含量进行校准和验证。校准和验证的所有 PB 值都超过 35%。校准模型用于评估湿地管理和温度升高对 N 去除的影响。此外，基于鸟类调查数据开发了加性回归模型 (ARM)，用于分析鸟类掉落的季节性模式，并了解它们对所研究湿地水质的影响。根据模型的结果，湿地水质受水禽种群的影响，最终受每个湿地单元的可用水量控制。湿地的氮去除量受到灌溉水量的负面影响。此外，温度升高导致水禽数量减少，导致氮浓度降低高达 42%。总体而言，结果表明开发的模型可以有效地用于量化湿地管理对水平衡、水质和植被的影响，并描述湿地管理、水资源利用和管理湿地生态系统服务功能的关系。温度升高导致水禽数量减少，导致氮浓度降低多达 42%。总体而言，结果表明开发的模型可以有效地用于量化湿地管理对水平衡、水质和植被的影响，并描述湿地管理、水资源利用和管理湿地生态系统服务功能的关系。温度升高导致水禽数量减少，导致氮浓度降低多达 42%。总体而言，结果表明开发的模型可以有效地用于量化湿地管理对水平衡、水质和植被的影响，并描述湿地管理、水资源利用和管理湿地生态系统服务功能的关系。