Sự thành công của những nỗ lực để khôi phục và / hoặc cải thiện chất lượng của các hồ và hồ chứa phụ thuộc vào triệt để chẩn đoán và đánh giá trước khi bắt đầu các biện pháp phục hồi. Việc chẩn đoán kỹ lưỡng với các phương pháp tiên đoán thích hợp cho phép kỳ vọng thực tế. Chương này mô tả như sau: (1) thành phần và các biến cần được xác định trong lưu vực sông và các hồ và trầm tích của nó; (2) số lượng mẫu cần thiết và tần số của họ;. | 3 Lake and Reservoir Diagnosis and Evaluation INTRODUCTION The success of efforts to restore and or improve the quality of lakes and reservoirs depends on the thoroughness of the diagnosis and evaluation prior to initiating restoration measures. Thorough diagnosis with appropriate predictive methods allows realistic expectations. This chapter describes the following 1 the constituents and variables that should be determined in the watershed and in the lake and its sediment 2 the sample number needed and their frequency 3 ways to express the data collected 4 the levels of constituents that indicate trophic state and 5 how to determine the limiting nutrient. Also it covers aspects of phosphorus modeling how to predict the response to treatment and how to choose a treatment s based on predicted response past success and cost. There have been many mistakes made in the name of lake restoration and management. Techniques that are the correct choice in some situations have been used in the wrong circumstances sometimes for political reasons but sometimes because the diagnosis and evaluation were inadequate Peterson et al. 1995 . Techniques such as external controls on nutrient input and in-lake controls such as drawdown to control macrophytes were implemented without the benefit of a complete prerestoration diagnosis evaluation. Improvement in water quality or an acceptable control of macrophytes did not occur because certain factors conditions were not considered fully such as 1 the relative unimportance of external nutrient sources compared to internal sources 2 the uncertainty of drawdown as a macrophyte control under the particular climatic conditions . Long Lake Washington Chapter 13 or 3 the natural condition of other lakes in the region . unreasonable expectations Peterson et al. 1999 . In other instances in-lake nutrient control measures were initiated where the major inputs were external and similarly improvements in water quality did not result . .
