Characterization of aquatic environments in the De Ondas River, Bahian Cerrado

This work sought to characterize the types of environments present in the De Ondas River, with the aim of obtaining information on their structural complexity and supporting public policies for water resource management that will allow the shared water use and will protect the biodiversity of the river basin. The De Ondas River watershed is located in the Cerrado Region, in the western part of Bahia State, and covers an area of 5.559 km². In order to perform the characterization, two stretches were demarcated, one in the upper part of the basin and another in the lower. Afterwards, a topobathymetric survey was conducted, and characterizations of the bottom and of hydraulic properties were done for both the rainy and dry seasons. The topobathymetric survey in the upper course showed altitudes ranging from 699.82 m to 714.06, whereas in the lower course these varied from 439.45 m to 446.91 m. Bathymetric profiles allowed the visualization of the structure and distribution of the bottom of the channel environments. The granulometric analysis of the higher part of the basin showed that sand was predominant (88.94%), while in the lower part boulders (76.9%) and cobble (23.1%) predominated. In the higher part of the basin, the water flow varied from 5.20 m³s-1 (dry period) to 9.07 m³s-1 (rainy period); and in the lower part, from 25.73 m³s-1 (dry period) to 66.44 m³s-1 (rainy period). The complexity of the environments of these stretches favors biological diversity in the river, resulting in different environments that aid aquatic species in adapting to the channel structure. The study of the physical characteristics of the De Ondas River produced a great amount of information regarding the micro-environments of the stretches examined, and will support studies related to aquatic biota and water resource management.

本研究旨在对德翁达斯河（De Ondas River）流域内的各类生境进行表征，以获取其结构复杂度相关信息，并为水资源管理的公共政策制定提供支撑，从而实现水资源的共享利用，同时保护该流域的生物多样性。德翁达斯河流域位于巴伊亚州西部的塞拉多（Cerrado）生态区，流域面积为5.559平方千米。为完成生境表征工作，本研究划定了两处河段：一处位于流域上游，另一处位于流域下游。随后，研究团队开展了地形水深测量，并针对雨季与旱季两个时段，分别对河段底质与水力特性进行了表征分析。上游河段的地形水深测量结果显示，海拔范围为699.82米至714.06米；下游河段的海拔则介于439.45米至446.91米之间。水深剖面数据可直观呈现河道生境的底床结构与分布特征。流域上游河段的底质粒度分析结果表明，沉积物以砂粒为主，占比达88.94%；而下游河段则以漂石（76.9%）与卵石（23.1%）为主。上游河段的流量在旱季为5.20立方米每秒，雨季增至9.07立方米每秒；下游河段的流量则从旱季的25.73立方米每秒，提升至雨季的66.44立方米每秒。上述两段河道的生境复杂度较高，有利于提升河流的生物多样性，形成多样化的生境条件，助力水生生物适应河道结构特征。本研究对德翁达斯河物理特性的分析，为所考察河段的微生境提供了大量详实数据，可为水生生物群落研究与水资源管理工作提供有力支撑。