• Title/Summary/Keyword: 비인

Search Result 134,340, Processing Time 0.145 seconds

A Study on the Growth Diagnosis and Management Prescription for Population of Retusa Fringe Trees in Pyeongji-ri, Jinan(Natural Monument No. 214) (진안 평지리 이팝나무군(천연기념물 제214호)의 생육진단 및 관리방안)

  • Rho, Jae-Hyun;Oh, Hyun-Kyung;Han, Sang-Yub;Choi, Yung-Hyun;Son, Hee-Kyung
    • Journal of the Korean Institute of Traditional Landscape Architecture
    • /
    • v.36 no.3
    • /
    • pp.115-127
    • /
    • 2018
  • This study was attempted to find out the value of cultural assets through the clear diagnosis and prescription of the dead and weakness factors of the Population of Retusa Fringe Trees in Pyeongji-ri, Jinan(Natural Monument No. 214), The results are as follows. First, Since the designation of 13 natural monuments in 1968, since 1973, many years have passed since then. In particular, despite the removal of some of the buried soil during the maintenance process, such as retreating from the fence of the primary school after 2010, Second, The first and third surviving tree of the designated trees also have many branches that are dead, the leaves are dull, and the amount of leaves is small. vitality of tree is 'extremely bad', and the first branch has already been faded by a large number of branches, and the amount of leaves is considerably low this year, so that only two flowers are bloomed. The second is also in a 'bad'state, with small leaves, low leaf density, and deformed water. The largest number 1 in the world is added to the concern that the s coverd oil is assumed to be paddy soils. Third, It is found that the composition ratio of silt is high because it is known as '[silty loam(SiL)]'. In addition, the pH of the northern soil at pH 1 was 6.6, which was significantly different from that of the other soil. In addition, the organic matter content was higher than the appropriate range, which is considered to reflect the result of continuous application for protection management. Fourth, It is considered that the root cause of failure and growth of Jinan pyeongji-ri Population of Retusa Fringe Trees group is chronic syndrome of serious menstrual deterioration due to covered soil. This can also be attributed to the newly planted succession and to some of the deaths. Fifthly, It is urgent to gradually remove the subsoil part, which is estimated to be the cause of the initial damage. Above all, it is almost impossible to remove the coverd soil after grasping the details of the soil, such as clayey soil, which is buried in the rootstock. After removal of the coverd soil, a pestle is installed to improve the respiration of the roots and the ground with Masato. And the dead 4th dead wood and the 5th and 6th dead wood are the best, and the lower layer vegetation is mown. The viable neck should be removed from the upper surface, and the bark defect should undergo surgery and induce the development of blindness by vestibule below the growth point. Sixth, The underground roots should be identified to prepare a method to improve the decompression of the root and the respiration of the soil. It is induced by the shortening of rotten roots by tracing the first half of the rootstock to induce the generation of new roots. Seventh, We try mulching to suppress weed occurrence, trampling pressure, and soil moisturizing effect. In addition, consideration should be given to the fertilization of the foliar fertilizer, the injection of the nutrients, and the soil management of the inorganic fertilizer for the continuous nutrition supply. Future monitoring and forecasting plans should be developed to check for changes continuously.

A Study on the Improvement Plans of Police Fire Investigation (경찰화재조사의 개선방안에 관한 연구)

  • SeoMoon, Su-Cheol
    • Journal of Korean Institute of Fire Investigation
    • /
    • v.9 no.1
    • /
    • pp.103-121
    • /
    • 2006
  • We are living in more comfortable circumstances with the social developments and the improvement of the standard of living, but, on the other hand, we are exposed to an increase of the occurrences of tires on account of large-sized, higher stories, deeper underground building and the use of various energy resources. The materials of the floor in a residence modern society have been going through various alterations in accordance with the uses of a residence and are now used as final goods in interioring the bottom of apartments, houses and shops. There are so many kinds of materials you usually come in contact with, but in the first place, we need to make an experiment on the spread of the fire with the hypocaust used as the floors of apartments, etc. and the floor covers you usually can get easily. We, scientific investigators, can get in contact with the accidents caused by incendiarism or an accidental fire closely connected with petroleum stuffs on the floor materials that give rise to lots of problems. on this account, I'd like to propose that we conduct an experiment on fire shapes by each petroleum stuff and that discriminate an accidental tire from incendiarism. In an investigation, it seems that finding a live coal could be an essential part of clearing up the cause of a tire but it could not be the cause of a fire itself. And besides, all sorts of tire cases or fire accidents have some kind of legislation and standard to minimize and at an early stage cope with the damage by tires. That is to say, we are supposed to install each kind of electric apparatus, automatic alarm equipment, automatic fire extinguisher in order to protect ourselves from the danger of fires and check them at any time and also escape urgently in case of fire-outbreaking or build a tire-proof construction to prevent flames from proliferating to the neighboring areas. Namely, you should take several factors into consideration to investigate a cause of a case or an accident related to fire. That means it's not in reason for one investigator or one investigative team to make clear of the starting part and the cause of a tire. accordingly, in this thesis, explanations would be given set limits to the judgement and verification on the cause of a fire and the concrete tire-spreading part through investigation on the very spot that a fire broke out. The fire-discernment would also be focused on the early stage fire-spreading part fire-outbreaking resources, and I think the realities of police tire investigations and the problems are still a matter of debate. The cause of a fire must be examined into by logical judgement on the basis of abundant scientific knowledge and experience covering the whole of fire phenomena. The judgement of the cause should be made with fire-spreading situation at the spot as the central figure and in case of verifying, you are supposed to prove by the situational proof from the traces of the tire-spreading to the fire-outbreaking sources. The causal relation on a fire-outbreak should not be proved by arbitrary opinion far from concrete facts, and also there is much chance of making mistakes if you draw deduction from a coincidence. It is absolutely necessary you observe in an objective attitude and grasp the situation of a tire in the investigation of the cause. Having a look at the spot with a prejudice is not allowed. The source of tire-outbreak itself is likely to be considered as the cause of a tire and that makes us doubt about the results according to interests of the independent investigators. So to speak, they set about investigations, the police investigation in the hope of it not being incendiarism, the fire department in the hope of it not being problems in installments or equipments, insurance companies in the hope of it being any incendiarism, electric fields in the hope of it not being electric defects, the gas-related in the hope of it not being gas problems. You could not look forward to more fair investigation and break off their misgivings. It is because the firing source itself is known as the cause of a fire and civil or criminal responsibilities are respected to the firing source itself. On this occasion, investigating the cause of a fire should be conducted with research, investigation, emotion independent, and finally you should clear up the cause with the results put together.

  • PDF

Study of East Asia Climate Change for the Last Glacial Maximum Using Numerical Model (수치모델을 이용한 Last Glacial Maximum의 동아시아 기후변화 연구)

  • Kim, Seong-Joong;Park, Yoo-Min;Lee, Bang-Yong;Choi, Tae-Jin;Yoon, Young-Jun;Suk, Bong-Chool
    • The Korean Journal of Quaternary Research
    • /
    • v.20 no.1 s.26
    • /
    • pp.51-66
    • /
    • 2006
  • The climate of the last glacial maximum (LGM) in northeast Asia is simulated with an atmospheric general circulation model of NCAR CCM3 at spectral truncation of T170, corresponding to a grid cell size of roughly 75 km. Modern climate is simulated by a prescribed sea surface temperature and sea ice provided from NCAR, and contemporary atmospheric CO2, topography, and orbital parameters, while LGM simulation was forced with the reconstructed CLIMAP sea surface temperatures, sea ice distribution, ice sheet topography, reduced $CO_2$, and orbital parameters. Under LGM conditions, surface temperature is markedly reduced in winter by more than $18^{\circ}C$ in the Korean west sea and continental margin of the Korean east sea, where the ocean exposed to land in the LGM, whereas in these areas surface temperature is warmer than present in summer by up to $2^{\circ}C$. This is due to the difference in heat capacity between ocean and land. Overall, in the LGM surface is cooled by $4{\sim}6^{\circ}C$ in northeast Asia land and by $7.1^{\circ}C$ in the entire area. An analysis of surface heat fluxes show that the surface cooling is due to the increase in outgoing longwave radiation associated with the reduced $CO_2$ concentration. The reduction in surface temperature leads to a weakening of the hydrological cycle. In winter, precipitation decreases largely in the southeastern part of Asia by about $1{\sim}4\;mm/day$, while in summer a larger reduction is found over China. Overall, annual-mean precipitation decreases by about 50% in the LGM. In northeast Asia, evaporation is also overall reduced in the LGM, but the reduction of precipitation is larger, eventually leading to a drier climate. The drier LGM climate simulated in this study is consistent with proxy evidence compiled in other areas. Overall, the high-resolution model captures the climate features reasonably well under global domain.

  • PDF

Soil Surface Fixation by Direct Sowing of Zoysia japonica with Soil Improvement on the Dredged Soil Slope (해저준설토 사면에서 개량제 처리에 의한 한국들잔디 직파 지표고정 공법에 관한 연구)

  • Jeong, Yong-Ho;Lee, Im-Kyun;Seo, Kyung-Won;Lim, Joo-Hoon;Kim, Jung-Ho;Shin, Moon-Hyun
    • Journal of the Korean Society of Environmental Restoration Technology
    • /
    • v.14 no.4
    • /
    • pp.1-10
    • /
    • 2011
  • This study was conducted to compare the growth of Zoysia japonica depending on different soil treatments in Saemangeum sea dike, which is filled with dredged soil. Zoysia japonica was planted using sod-pitching method on the control plot. On plots which were treated with forest soil and soil improvement, Zoysia japonica seeds were sprayed mechanically. Sixteen months after planting, coverage rate, leaf length, leaf width, and root length were measured and analyzed. Also, three Zoysia japonica samples per plot were collected to analyze nutrient contents. Coverage rate was 100% in B treatment plot(dredged soil+$40kg/m^3$ soil improvement+forest soil), in C treatment plots (dredged soil+$60kg/m^3$ soil improvement+forest soil), and D treatment plots (dredged soil+$60kg/m^3$ soil improvement), while only 43% of the soil surface was covered with Zoysia japonica on control plots. The width of the leaf on C treatment plots (3.79mm) was the highest followed by D treatment (3.49mm), B treatment (2.40mm) and control plots (1.97mm). Leaf and root length of D treatment was 30.18cm and 13.18cm, which were highest among different treatments. The leaf length of D treatment was highest followed by C, B, and A treatments. The root length of D treatment was highest followed by C, A, and B treatments. The nitrogen and phosphate contents of the above ground part of Zoysia japonica were highest in C treatment, followed by D, B, and A treatments. The nitrogen and phosphate contents of the underground part of Zoysia japonica were highest in D treatment, followed by C, A, and B treatments. C and D treatments showed the best results in every aspect of grass growth. The results of this study could be used to identify the cost effective way to improve soil quality for soil surface fixation on reclaimed areas using grass species.

The Effects of Seeding Pattern and Rate on the Yield and Agronomic Characters of Barley Under Different Cultural Conditions (대맥의 파종양식 및 파종밀도가 몇가지 재배조건하에서의 수량 및 주요실용형질에 미치는 영향)

  • Pyeong-Ki Yim
    • KOREAN JOURNAL OF CROP SCIENCE
    • /
    • v.21 no.1
    • /
    • pp.136-179
    • /
    • 1976
  • Effects of seeding pattern and rate on the yield and some agronomic characters of barley under different cultural conditions were observed at Suweon, Daejeon and Jinju during the barley growing season from 1972 to 1974. Plant height and culm length were increased by dense seeding, shading, heavy fertilization, moving location down to the lower latitude. The tiller number per plant, dry matter weight, leaf number on main stem, percentage of valid tillers, RGR, NAR, and $R_{A}$ were increased by heavy fertilization, sparse seeding, reduced furrow width and drilling likewise the length, width and angle of leaf. The newer cultivar had higher RGR and NAR. The higher yielding cultivars had higher potential for carbohydrate assimilating ability. Straw weight and grain yield were increased by dense seeding, reduced furrow width, drilling, heavier fertilization and moving the location to the south, and then decreased by shading and late seeding. High yield increase by drilling was found in late seeding. The optimum seeding rate for the yield increase were 15l/10a for furrow and 25l/10a for drilling. The spike number type cultivars were favourable for the sparse seeding and the spike weight type cultivars seemed to be suitable to the dense seeding, The repeatability of days to heading due to location and fertilizer level was higher than that of seeding time and seeding method. Repeatability of culm length was extremly high in seeding method and comparatively high in fertilizer level while low in location. The repeatability of yield due to location and seeding methods was comparatively high, but the tendency was different along with different cultivars. Also the repeatability of yield due to the fertilizer level was generally high except cultivar Haganemngi.

  • PDF

Double Cropping Productivity of Main Whole-Crop Silage Rice and Winter Feed Crops in the Central Plains of Korea (중부 평야지에서 사료용 벼와 주요 동계사료작물 이모작 시 생산성)

  • Ahn, Eok-Keun;Jeong, Eung-Gi;Park, Hyang-Mi;Jung, Kuk-Hyun;Hyun, Ung-Jo;Ku, Ja-Hwan
    • KOREAN JOURNAL OF CROP SCIENCE
    • /
    • v.64 no.4
    • /
    • pp.311-322
    • /
    • 2019
  • In order to establish an optimal double cropping system to obtain the maximum annual quantity, we investigated the annual productivity of whole-crop silage (WCS) rice, Jowoo (Jw), Yeongwoo (Yw), and Mogwoo (Mw), and winter feed crops (WFC), Italian ryegrass (IRG), Greenfarm (GF), rye Gogu (GU), and triticale Joseong (JS), in paddy fields of the central plains of Korea. From 2016 to 2019, each crop was subjected to two standard cultivation methods: WCS rice and WFC optimal. Using the WCS optimal mode, the average dry matter yield (DMY) of WCS rice, early flowering Jw, was 15.8 tons/ha and 21.0 for the mid-late heading Yw; there was no significant difference compared to the 19.2 tons/ha late-flowering Mw (p<0.01). The WFC were not significantly different between GF (3.2 tons/ha) and GU (4.5) sown on September 23rd, while JS was the highest at 12.6 tons/ha (p<0.001). There was a significant difference in the order of JS (16.6 tons/ha) > GF (10.5) > GU (4.7)(p<0.001) sown on October 11th. For JS sown on October 31st, the DMY was 11.8 tons/ha, which was significantly higher than that of the other two crops (p<0.05). Except for rye GU, DMY was the highest when sown on October 11th. For WFC optimal mode, the average DMY of JS was the highest at 18.3 tons/ha, which was significantly different from that of GF (10.9) and GU (9.6) (p<0.001). The DMY of WCS rice transplanted on May 10th was the highest at 23.0 tons/ha in Mw, which was not significantly different from that of Yw (21.4) but significantly different from that of Jw (15.9) (p<0.05). On transplanting on May 25th, the DMY of Mw was the highest at 24.2 tons/ha; this was not significantly different from that of Yw (20.7), but it was significantly different from that of Jw (18.6) (p<0.05). When transplanted on June 11th, the DMY was 21.3 tons/ha in Yw, which was significantly higher than the DMY of other two cultivars, Jw and Mw (p<0.05). For the WCS rice-WFC double cropping, the total annual DMY was 33.6 tons/ha with the combination of the WCS rice, Yw, and the triticale JS for WCS optimal mode. Meanwhile, the total annual DMY was 39.6 tons/ha with the combination of the triticale JS and the WCS rice, Yw, for WFC optimal mode. In conclusion, the strategies for obtaining the maximum yield of high-quality forage for WCS rice-WFC, WFC-WCS rice double cropping are as follows: 1) cultivation centered on the optimal mode of WFC, and 2) sowing the WFC, triticale JS in mid-October, harvesting the crops around the end of May and transplanting the WCS rice, Yw, in early June to obtain the maximum DMY of 39.6 tons/ha.

Diagnosis of the Field-Grown Rice Plant -[1] Diagnostic Criteria by Flag Leaf Analysis- (포장재배(圃場栽培) 수도(水稻)의 영양진단(營養診斷) -1. 지엽분석(止葉分析)에 의(依)한 진단(診斷)-)

  • Park, Hoon
    • Applied Biological Chemistry
    • /
    • v.16 no.1
    • /
    • pp.18-30
    • /
    • 1973
  • The flag and lower leaves (4th or 5th) of rice plant from the field of NPK simple trial and from three low productive area were analyzed in order to find out certain diagnostic criteria of nutritional status at harvest. 1. Nutrient contents in the leaves from no fertilizer, minus nutrient and fertilizer plots revealed each criterion for induced deficiency (severe deficient case induced by other nutrients), deficiency (below the critical concentration), insufficiency (hidden hunger region), sufficiency (luxuary consumption stage) and excess (harmful or toxic level). 2. Nitrogen contents for the above five status was less than 1.0%, 1.0 to 1.2, 1.2 to 1.6, 1.6 to 1.9 and greater than 1.9, respectively. 3. It was less than 0.3%, 0.3 to 0.4, 0.4 to 0.55 and greater than 0.55 for phosphorus $(P_2O_5)$ but excess level was not clear. 4. It was below 0.5%, 0.5 to 0.9, 0.9 to 1.2, 1.2 to 1.4 and above 1.4 for potassium. 5. It was below 4%, 4 to 6, 6 to 11 and above 11 for silicate $(SiO_2)$ and no excess was appeared. 6. Potassium in flag leaf seemed to crow out nitrogen to ear resulting better growth of ear by the inhibition of overgrowth of flag leaf. 7. Phosphorus accelerated the transport of Mg, Si, Mn and K in this order from lower leaf to flag, and retarded that of Ca and N in this order at flowering while potassium accelerated in the order of Mn, and Ca, and retarded in the order of Mg, Si, P and N at milky stage. 8. Transport acceleration index (TAI) expressed as (F_2L_1-F_1L_2)\;100/F_1L_1$ where F and L stand for other nutrient cotents in flag and lower leaf and subscripts indicate the rate of a nutrient applied, appears to be suitable for the effect of the nutrient on the translocation of others. 9. The content of silicate $(SiO_2)$ in the flag was lower than that of lower leaf in the early season cultivation indicating hinderance in translocation or absorption. It was reverse in the normal season cultivation. 10. The infection rate of Helminthosporium frequently occurred in the potassium deficient field seemed to be related more to silicate and nitrogen content than potassium in the flag leaf. 11. Deficiency of a nutrient occured simultaniously with deficiency of a few other ones. 12. Nutritional disorder under the field condition seems mainly to be attributed to macronutrients and the role of micronutrient appears to be none or secondary.

  • PDF

Batch Scale Storage of Sprouting Foods by Irradiation Combined with Natural Low Temperature - III. Storage of Onions - (방사선조사(放射線照射)와 자연저온(自然低溫)에 의한 발아식품(發芽食品)의 Batch Scale 저장(貯藏)에 관한 연구(硏究) - 제3보(第三報) 양파의 저장(貯藏) -)

  • Cho, Han-Ok;Kwon, Joong-Ho;Byun, Myung-Woo;Yang, Ho-Sook
    • Applied Biological Chemistry
    • /
    • v.26 no.2
    • /
    • pp.82-89
    • /
    • 1983
  • In order to develop a commercial storage method of onions by irradiation combined with natural low temperature, two local varieties of onions, precocious species and late ripening, were stored at natural low temperature storage room ($450{\times}650{\times}250cmH.$; year-round temperature change, $2{\sim}17^{\circ}C$; R.H., $80{\sim}85%$) on batch scale following irradiation with optimum dose level. Precocious and late varieties were all sprouted after five to seven months storage, whereas $10{\sim}15$ Krad irradiated precocious variety was $2{\sim}4%$ sprouted after nine months storage, but sprouting was completly inhibited at the same dose for late variety. The extent of loss due to rot attack after ten months storage were $23{\sim}49%$ in both control and irradiated group of precocious variety but those of late variety were only $4{\sim}10%$. The weight loss of irradiated precocious variety after ten months storage was $13{\sim}16$, while that of late variety was $5.3{\sim}5.9%$ after nine months storage. The moisture content, during whole storage period, of two varieties were $90{\sim}93$ with negligible changes. The total sugar content differed little with varieties and doses immediatly after irradiation, but decreased by the elapse of storage period. 33.6% of its content was decreased in control and 12.5% in irradiated group but $20{\sim}26$ decreased in both control and irradiated group of late variety after nine months storage. No appreciable change was observed immediately after irradiation irrespective of variety and dose, but decreased slightly with storage. Ascorbic acid content of precocious variety was increased slightly with dose immediately after irradiation, but those of late variety decreased slightly. Ascorbic acid content were generally decreased during whole storage period. An economical preservation method of onions appliable to late variety, would be to irradiate onion bulbs at dost range of $10{\sim}15$ Krad followed by storage at natural low temperature storage room.

  • PDF

A survey on the nutrient intake and food consumption of the students at the dormitories, College of Agriculture, Seoul National University (서울대학교(大學校) 농과대학(農科大學) 남녀(男女) 기숙사생(寄宿舍生)의 영양섭취(營養攝取) 조사(調査))

  • Mo, Su-Mi;Han, In-Kyu;Kim, Ze-Uook;Lee, Chun-Yung;Kim, Ho-Sik
    • Applied Biological Chemistry
    • /
    • v.7
    • /
    • pp.92-104
    • /
    • 1966
  • For the purpose of the better dietary management and to empahsize of importance in nutrition education for 552 students at the dormitories, College of Agriculture, Seoul National University, the dietary survey was conducted for each consecutive seven days, from March 7th to 13th at the boy's dormitory, from March 14th to 20th at the girl's dormitory, respectively. In comparison the average caloric and nutrient intake per caput per day at the both, girl's and boy's dormitory with the recommended dietary allowances for age of 25, the intake of calories and all nutrients except riboflavin were over the allowances for the boy, while the caloric intake by the girl was considerablly below the allowance. But it is meant that only 150 calories was actually deficient in comparison with the figure of the average energy consumption determined for the girls at the dormitory of the Sook-myung Woman's University, whose pattern of living was quite similar to those of the girls at this college. Except iron and ascorbic acid, all other nutrients were deficient for the girls. The calories in the form of protein of a diet taken by the boy was 12.9% and that by the girl was 12.8%. Protein quality of the diet taken by boy scored 70 while that by the girl scored 79. NDp Cal% of the diet taken by the boy was 7 and that by the girl was figured out to be 8. Therefore, calculated reference protein taken by the boy was 55.8 grams and that by the girl was 36.9%. Though it is generally recommended that at least 1/3 of the protein should come from animal sources, it was apparent by this survey that providing 1/5 of the protein from animal sources with remaining part of high quality vegetable protein foods in the adequate mixed diet would give satisfactory results for both girl and boy students. This was clearly demonstrated by the recommended reference protein and NDp Cal% met. Significant difference between boys and girls in the average consumption of seasonings was found. In consumption per day of seasonings, boy used 1.5 grams of red pepper powder which means they used 15 times more of red pepper than girls did. Kochujang was used 13 grams by boy-students which was as high as 21 times of that of the girl. Total salt intake by the boy was 34 grams while the girl consummed 23 grams. It is obviously recognized that boys prefer more peppery and salty flavor than girls do. To reduce the amount of protein consummed and to improve the quality of protein food, increase of riboflavin rich food and increase of fat intake in place of grain intake are recommendable to the boy. For the girl's diet, consumption of grains, particularly more intake of barley mal· be recommendable to meet the B group of vitamins allowances as well as the caloric allowance. The use of more servings of yellow green vegetables is needed to the girl.

  • PDF

Calculation of Unit Hydrograph from Discharge Curve, Determination of Sluice Dimension and Tidal Computation for Determination of the Closure curve (단위유량도와 비수갑문 단면 및 방조제 축조곡선 결정을 위한 조속계산)

  • 최귀열
    • Magazine of the Korean Society of Agricultural Engineers
    • /
    • v.7 no.1
    • /
    • pp.861-876
    • /
    • 1965
  • During my stay in the Netherlands, I have studied the following, primarily in relation to the Mokpo Yong-san project which had been studied by the NEDECO for a feasibility report. 1. Unit hydrograph at Naju There are many ways to make unit hydrograph, but I want explain here to make unit hydrograph from the- actual run of curve at Naju. A discharge curve made from one rain storm depends on rainfall intensity per houre After finriing hydrograph every two hours, we will get two-hour unit hydrograph to devide each ordinate of the two-hour hydrograph by the rainfall intensity. I have used one storm from June 24 to June 26, 1963, recording a rainfall intensity of average 9. 4 mm per hour for 12 hours. If several rain gage stations had already been established in the catchment area. above Naju prior to this storm, I could have gathered accurate data on rainfall intensity throughout the catchment area. As it was, I used I the automatic rain gage record of the Mokpo I moteorological station to determine the rainfall lntensity. In order. to develop the unit ~Ydrograph at Naju, I subtracted the basic flow from the total runoff flow. I also tried to keed the difference between the calculated discharge amount and the measured discharge less than 1O~ The discharge period. of an unit graph depends on the length of the catchment area. 2. Determination of sluice dimension Acoording to principles of design presently used in our country, a one-day storm with a frequency of 20 years must be discharged in 8 hours. These design criteria are not adequate, and several dams have washed out in the past years. The design of the spillway and sluice dimensions must be based on the maximun peak discharge flowing into the reservoir to avoid crop and structure damages. The total flow into the reservoir is the summation of flow described by the Mokpo hydrograph, the basic flow from all the catchment areas and the rainfall on the reservoir area. To calculate the amount of water discharged through the sluiceCper half hour), the average head during that interval must be known. This can be calculated from the known water level outside the sluiceCdetermined by the tide) and from an estimated water level inside the reservoir at the end of each time interval. The total amount of water discharged through the sluice can be calculated from this average head, the time interval and the cross-sectional area of' the sluice. From the inflow into the .reservoir and the outflow through the sluice gates I calculated the change in the volume of water stored in the reservoir at half-hour intervals. From the stored volume of water and the known storage capacity of the reservoir, I was able to calculate the water level in the reservoir. The Calculated water level in the reservoir must be the same as the estimated water level. Mean stand tide will be adequate to use for determining the sluice dimension because spring tide is worse case and neap tide is best condition for the I result of the calculatio 3. Tidal computation for determination of the closure curve. During the construction of a dam, whether by building up of a succession of horizontael layers or by building in from both sides, the velocity of the water flowinii through the closing gapwill increase, because of the gradual decrease in the cross sectional area of the gap. 1 calculated the . velocities in the closing gap during flood and ebb for the first mentioned method of construction until the cross-sectional area has been reduced to about 25% of the original area, the change in tidal movement within the reservoir being negligible. Up to that point, the increase of the velocity is more or less hyperbolic. During the closing of the last 25 % of the gap, less water can flow out of the reservoir. This causes a rise of the mean water level of the reservoir. The difference in hydraulic head is then no longer negligible and must be taken into account. When, during the course of construction. the submerged weir become a free weir the critical flow occurs. The critical flow is that point, during either ebb or flood, at which the velocity reaches a maximum. When the dam is raised further. the velocity decreases because of the decrease\ulcorner in the height of the water above the weir. The calculation of the currents and velocities for a stage in the closure of the final gap is done in the following manner; Using an average tide with a neglible daily quantity, I estimated the water level on the pustream side of. the dam (inner water level). I determined the current through the gap for each hour by multiplying the storage area by the increment of the rise in water level. The velocity at a given moment can be determined from the calcalated current in m3/sec, and the cross-sectional area at that moment. At the same time from the difference between inner water level and tidal level (outer water level) the velocity can be calculated with the formula $h= \frac{V^2}{2g}$ and must be equal to the velocity detertnined from the current. If there is a difference in velocity, a new estimate of the inner water level must be made and entire procedure should be repeated. When the higher water level is equal to or more than 2/3 times the difference between the lower water level and the crest of the dam, we speak of a "free weir." The flow over the weir is then dependent upon the higher water level and not on the difference between high and low water levels. When the weir is "submerged", that is, the higher water level is less than 2/3 times the difference between the lower water and the crest of the dam, the difference between the high and low levels being decisive. The free weir normally occurs first during ebb, and is due to. the fact that mean level in the estuary is higher than the mean level of . the tide in building dams with barges the maximum velocity in the closing gap may not be more than 3m/sec. As the maximum velocities are higher than this limit we must use other construction methods in closing the gap. This can be done by dump-cars from each side or by using a cable way.e or by using a cable way.

  • PDF